From First and Second Timothy, Titus by George T. Montague, commenting on 2 Timothy 1:6-8, 13-14
If there was any doubt about the meaning of “what has been entrusted to me” in 1:12, it is removed by this passage, which clearly speaks of Paul’s teaching as the trust, now confided to Timothy. Timothy must follow the norm (hypotypōsis) set by the teaching of Paul, his very words. The Greek word is sometimes used for the architect’s plan for a building, the pattern for a cloak, the outline of a speech, the first sketch of a painting.
On the one hand, Paul’s words set the direction for Timothy’s teachings, but, on the other, he is not expected simply to mouth the phrases of his mentor. He is to fill them out, using his judgment as to how these words apply to situations unforeseen by Paul. This is a magnificent image for a dynamic tradition.
The same dynamic is at work in Jesus’ teaching in the Gospels. Jesus did not tell his disciples to parrot his words without concern for changing circumstances. His disciples were to convey his message as a seed meant to grow and bear fruit in whatever soil it was planted (Mark 4:14–20), bringing greater understanding and development. As Vatican Council II put it, traditio proficit, crescit perceptio: “The tradition . . . develops. . . . There is a growth in the understanding” (Dei Verbum 8).