Strait Gate
The image of the strait — that is, narrow — gate or door belongs to Jesus' teaching on the difficulty of entering the kingdom. The single saying preserved within UPDV's scope frames entry as a striving against odds rather than a default outcome.
The Narrow Door
Asked whether those being saved are few, Jesus answers with an instruction rather than a number: "Strive to enter in by the narrow door: for many, I say to you⁺, will seek to enter in, and will not be able" (Lu 13:24). The verb is exertion ("strive"), and the geometry is constriction ("narrow door"). The saying turns the questioner's curiosity about the count into a charge to the questioner about the effort. Many will seek entry, the saying allows; entry, however, is not granted by seeking alone. It belongs to those who, finding the door narrow, push through it.