Assurance
Assurance, in the biblical vocabulary, is the believer's settled confidence that what God has promised God will do — confidence in being known by him, in being heard by him, in being kept by him through affliction and death, and in coming at last into the inheritance he has prepared. It is not a feeling that floats free of evidence. The texts root it in faith, in hope, in love, in the Spirit's inner witness, and in the keeping of God's commandments, and they make the same point from many angles: the saint may know.
Produced by Faith
The first ground of assurance is faith in Christ. In him "we have boldness and access in confidence through our faith in him" (Eph 3:12). Paul's own example reduces it to the simplest grammar: "I know him whom I have believed, and I am persuaded that he is able to guard that which I have committed to him against that day" (2Ti 1:12). The exhortation of Hebrews follows the same line — "let us draw near with a true heart in fullness of faith, having our hearts sprinkled from an evil conscience, and having our body washed in pure water" (Heb 10:22). The drawing near is itself a posture of assurance.
Made Full by Hope
Faith is consummated by hope, and hope, in turn, gives assurance its forward tilt. Hebrews urges every believer to "show the same diligence to the fullness of hope even to the end" (Heb 6:11), and names that hope as "an anchor of the soul; both sure and steadfast; and entering into that which is inside the veil" (Heb 6:19). The image is structural: an anchor that has already taken hold inside the sanctuary.
Confirmed by Love
Love confirms what faith and hope claim. "We know that we have passed out of death into life, because we love the brothers. He who does not love stays in death" (1Jn 3:14). Love is the test that displaces fear: "There is no fear in love: but perfect love casts out fear, because fear has punishment; and he who fears has not been made perfect in love" (1Jn 4:18). And in 1 John, love and obedience and the Spirit's gift fold together — "hereby we know that we stay in him and he in us, because he has given us of his Spirit" (1Jn 4:13).
The Effect of Righteousness
Isaiah states the principle in one line: "And the work of righteousness will be peace; and the effect of righteousness, quietness and confidence forever" (Isa 32:17). Where righteousness has gone to work, quietness and confidence are what is left.
Rich in the Understanding of the Gospel
Assurance is also a function of how clearly the gospel is grasped. Paul prays for the Colossians that their hearts may be comforted, "knit together in love, and to all riches of the full assurance of understanding, that they may know the mystery of God, [even] Christ" (Col 2:2). To the Thessalonians he reminds them that "our good news did not come to you⁺ in word only, but also in power, and in the Holy Spirit, and in much assurance" (1Th 1:5). The gospel itself, fully understood, produces the confidence it announces.
What the Saints May Know
The saints are privileged to know specific things. They may know their election: "Yahweh has set apart for himself him who is godly: Yahweh will hear when I call to him" (Ps 4:3); and Paul addresses his hearers as those "knowing, brothers beloved by God, your⁺ election" (1Th 1:4). They may know their redemption — Job's confession, "But as for me I know that my Redeemer lives, And at last he will stand up on the earth" (Job 19:25), is the prototype. They may know their adoption: "The Spirit himself bears witness with our spirit, that we are children of God" (Rom 8:16) and "Beloved, we are now children of God" (1Jn 3:2). They may know their salvation: "Look, [the Speech of] God is my salvation; I will trust, and will not be afraid; for Yah, Yahweh, is my strength and song; and he has become my salvation" (Isa 12:2). And they may know that they have eternal life — for John's stated purpose in writing was just this: "These things I have written to you⁺, that you⁺ may know that you⁺ have eternal life, [even] to you⁺ who believe on the name of the Son of God" (1Jn 5:13).
The Inseparable Love of God
Assurance reaches its highest pitch where Paul rests it on the love of God in Christ:
"For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers, nor height, nor depth, nor anything else in creation, will be able to separate us from the love of God, which is in Christ Jesus our Lord" (Rom 8:38-39).
Paul's "I am persuaded" is the assurance vocabulary at its strongest.
Union with God and Christ
The believer is not just rescued; the believer is joined. "Don't you⁺ know that your⁺ bodies are members of Christ?" Paul asks (1Co 6:15). To the same congregation he writes, "Try yourselves, whether you⁺ are in the faith; approve yourselves. Or don't you⁺ know as to yourselves, that Jesus Christ is in you⁺?" (2Co 13:5). Ephesians says it briefly — "we are members of his body" (Eph 5:30). And John gives the inward test: "whoever keeps his speech, in him truly has the love of God been perfected. Hereby we know that we are in him" (1Jn 2:5); "Hereby we know that we stay in him and he in us, because he has given us of his Spirit" (1Jn 4:13).
Peace with God
Justification carries with it a settled relationship: "Being therefore justified by faith, we have peace with God through our Lord Jesus Christ" (Rom 5:1).
Preservation
Assurance shows itself most plainly under threat. David sings, "I will not be afraid of ten thousands of the people Who have set themselves against me round about" (Ps 3:6); and again, "Though a host should encamp against me, My heart will not fear: Though war should rise against me, Even then I will be confident. … For in the day of trouble he will keep me secretly in his pavilion: In the covert of his tabernacle he will hide me; He will lift me up on a rock" (Ps 27:3-5). Korah's sons sing the same in the plural — "God is our refuge and strength, A very present help in trouble. Therefore we will not fear, though the earth changes, And though the mountains shake into the heart of the seas" (Ps 46:1-2). And Psalm 8 grounds the confidence in God's having "established strength… that you might still the enemy and the avenger" (Ps 8:2).
Answers to Prayer
A particular branch of assurance is confidence that prayer is heard. "And whatever we ask we receive of him, because we keep his commandments and do the things that are pleasing in his sight" (1Jn 3:22). And again, "this is the boldness which we have toward him, that, if we ask anything according to his will, he hears us: and if we know that he hears us whatever we ask, we know that we have the petitions which we have asked of him" (1Jn 5:14-15).
Comfort in Affliction
Affliction is where assurance is tested and where it speaks loudest. The psalmist confesses, "My flesh and my heart fails; [But] God is the strength of my heart and my portion forever" (Ps 73:26). Jesus announces in the synagogue at Nazareth, "The Spirit of Yahweh is on me, Because he anointed me to preach good news to the poor: He has sent me to proclaim release to the captives, And recovering of sight to the blind, To set at liberty those who are bruised" (Lu 4:18). And Paul catalogs the apostolic experience: "[we are] pressed on every side, yet not straitened; perplexed, yet not to despair; pursued, yet not forsaken; struck down, yet not destroyed; always bearing about in the body the dying of Jesus, that the life also of Jesus may be manifested in our body" (2Co 4:8-10). The conclusion he draws is the same: "though our outward man is decaying, yet our inward man is renewed day by day. For our light affliction, which is for the moment, works for us more and more exceedingly an eternal weight of glory" (2Co 4:16-17).
Continuance in Grace
Paul's confidence about the Philippians sums up the perseverance branch of assurance: he is "confident of this very thing, that he who began a good work in you⁺ will perfect it until the day of Christ Jesus" (Php 1:6).
A Support in Death
Assurance holds at the last threshold. Of the Davidic confessions, the most familiar speaks where life ends: "Yes, though I walk through the valley of the shadow of death, I will fear no evil; for [your Speech is with] me; Your rod and your staff, they comfort me" (Ps 23:4). The bracketed pronoun-resolution is the UPDV's, and it makes the protector explicit: it is the divine Speech that walks the valley with the singer.
A Glorious Resurrection
Beyond death the assurance reaches further still. Job continues from his "I know that my Redeemer lives": "And after my skin, [even] this [body], is destroyed, Then without my flesh will I see God" (Job 19:26). The psalmist matches the hope: "As for me, I will see your face in righteousness; I will be satisfied, when I awake, with [seeing] your form" (Ps 17:15). John promises the same vision: "We know that, if he will be manifested, we will be like him; for we will see him even as he is" (1Jn 3:2). Paul names the mechanism — Christ "will fashion anew the body of our humiliation, [that it may be] conformed to the body of his glory, according to the working by which he is able even to subject all things to himself" (Php 3:21).
A Kingdom and a Crown
The believer's inheritance is named under two figures. The kingdom: "receiving a kingdom that can't be shaken, let us have grace, by which we may offer service well-pleasing to God with reverence and awe" (Heb 12:28); and in the heavenly song, the redeemed are "to our God a kingdom and priests; and they will reign on the earth" (Rev 5:10). The crown: Paul's last words to Timothy speak of "the crown of righteousness, which the Lord, the righteous judge, will give to me at that day; and not to me only, but also to all those who have loved his appearing" (2Ti 4:8). And James generalizes the promise — "Blessed is the man who endures trial; for when he has been approved, he will receive the crown of life, which [the Lord] promised to those who love him" (Jas 1:12).
Diligence and Striving
Assurance, in the New Testament, is never separated from active diligence. "Therefore, brothers, be the more diligent to make your⁺ calling and election sure: for if you⁺ do these things, you⁺ will never stumble: for thus will be richly supplied to you⁺ the entrance into the eternal kingdom of Jesus Christ, our Lord and Savior" (2Pe 1:10-11). And Hebrews binds the keeping of assurance to perseverance: "we have become sharers of Christ, if we hold fast the beginning of our confidence firm to the end" (Heb 3:14). The warning of the wilderness generation in the surrounding verses (Heb 3:18) stands behind this exhortation — those who were disobedient did not enter rest.
When Assurance Falters
The Psalter does not pretend that the saints always feel what they know. The remedy it models is self-address: "Why are you cast down, O my soul? And why are you disquieted inside me? Hope in God; for I will yet praise him, My salvation and my God" (Ps 42:11). Confident hope in God is what restores assurance when it has been shaken.
Exemplified
David is the standing OT example. The same singer who walks the valley fearing no evil also confesses, "You will guide me with your counsel, And afterward receive me to glory. Whom have I in heaven [but you] And there is none on earth that I desire besides you. My flesh and my heart fails; [But] God is the strength of my heart and my portion forever" (Ps 73:24-26).
Paul is the standing NT example. His "I know him whom I have believed, and I am persuaded" (2Ti 1:12) is matched at the end of the same letter by the same note — "The Lord will deliver me from every evil work, and will save me to his heavenly kingdom: to whom [be] the glory forever and ever. Amen" (2Ti 4:18).
The Johannine summary captures the whole movement of the topic in a single line: "And hereby we will know that we are of the truth, and will assure our heart before him" (1Jn 3:19).