Needle
The needle appears in the gospels only in a single saying — the "eye of a needle" set against the rich man's entry into the kingdom of God. The tool of fine work becomes the picture of an opening too narrow for what is being asked to pass through it.
The eye of a needle
In the Markan form, the saying is given as a comparison of impossibilities: "It is easier for a camel to go through the eye of a needle, than for a rich man to enter into the kingdom of God" (Mr 10:25). The largest pack-animal in view is set against the smallest measurable opening; the contrast registers absolute narrowness.
The Lukan parallel keeps the same comparison: "For it is easier for a camel to enter in through a needle's eye, than for a rich man to enter into the kingdom of God" (Lu 18:25). Both sayings frame the rich man's entry as a thing harder than the already-impossible image of pushing a camel through.