"Oh that they were wise, that they understood this, that they would consider their latter end." Deut. 32:29
A friend put this chapter into song and he chose to repeat, "Oh that they were wise" and I was so happy that he did because it felt to me like it needed to be repeated. Being wise here is knowing your end, considering the latter end.
Years ago, I thought that a good technique for witnessing would be to simply ask, something about a person's future and then say, "Then what?" because eventually that will come to their "latter end."