First Nephi 3:8

And it came to pass that when my father had heard these words he was exceedingly glad, for he knew that I had been blessed of the Lord.

Lehi could tell his son had been blessed because he exhibited faith. Faith is a gift from God. We do not manufacture it. Nevertheless, we must prepare ourselves for the gift, we must ask and seek for it, and we must receive and act on it. Because Nephi showed faith, Lehi knew he had prepared himself and sought for it. Such an one is always blessed.