Continuous Giving

Why does Yitzchak's blessing to Yaakov begin with the word "and," when nothing came before it? Rashi and the Midrash Rabbah both notice the strange opening, and the Midrash hears in it a promise that Hashem will give, and then give again.A Rosh Yeshiva's idea about a child, his father and a credit card makes it concrete. It also asks how much of our own day is a quick payment to Hashem, and how much is a connection that keeps going.