Originally recorded in the 1600s, this proverb has its exact opposite in the phrase, “you can't teach old dogs new tricks.” Both sayings are used more to justify a choice - trying to learn something new or giving it up - rather than to inform a choice with intelligence. Sometimes it is rendered, “you are never too old to learn.”

Luke 22:39-44           

He [Jesus] came out and went, as was his custom, to the Mount of Olives; and the disciples followed him.  When he reached the place, he said to them, “Pray that you may not come into the time of trial.” Then he withdrew from them about a stone's throw, knelt down, and prayed,  “Father, if you are willing, remove this cup from me; yet, not my will but yours be done.”  [Then an angel from heaven appeared to him and gave him strength.  In his anguish he prayed more earnestly, and his sweat became like great drops of blood falling down on the ground.]

With Jesus at the Mount of Olives, we are very late in his earthly ministry.  In a sense, the disciples are only about to begin their ministry.  If you grant that prayer is a form of education, where God instructs, leads, supports and directs us, then Jesus is learning right up to the very end.  In addition, although Jesus had been preparing his students for his arrest and crucifixion, they still needed teaching.  In fact, they were still beyond hope of being taught.  Jesus clearly affirms
that it is never too late to learn, even for him!