Seventy Years for Dovid
Shown the soul of Dovid HaMelech with almost no life allotted to it, Adam gave him seventy years of his own.
The Midrash relates that Hashem passed every future generation before Adam, as the verse says, "This is the book of the generations of Adam." One by one he saw the souls that would descend from him. Then he came to Dovid, and saw that only three hours of life had been written for him.
Adam was pained. "Master of the world," he said, "is there no remedy for this one?" Hashem answered that this was how it had arisen in His thought. Adam asked how many years had been given to him, and Hashem told him: a thousand years. "May one give a gift in Heaven?" Adam asked. Hashem said that one may.
So Adam declared that seventy of his own years would belong to Dovid. He drew up a deed of gift and wrote it out, and the Midrash says it was signed by Hashem, by the angel Metatron and by Adam himself. Then Adam spoke again: "Master of the world, the beauty, the kingship and the songs of praise, all of it I give to him with these seventy years, so that he will live and sing before You."
Chazal note that Adam had been told he would die "on the day" he ate from the tree, and a day of Hashem is a thousand years. Because of his gift, Adam lived nine hundred and thirty years, seventy short of a thousand. Dovid became king at thirty and reigned for forty years, and he filled the seventy years Adam gave him with the songs of Tehillim that Jews have sung ever since.
Source: Yalkut Shimoni, Bereishis, remez 41 (on Bereishis 5:1); Midrash Bamidbar Rabbah 14:12.
Adam's gift cost him something real: seventy years of his own life. Most of our giving comes from what we have to spare. This week, choose one gift that truly costs you: an hour you had planned for yourself, spent with someone lonely; a call to a person who needs your patience more than your money. Do it quietly, without being asked, and let it help someone else sing in a way they could not on their own.