'Childhood' in the Bible

And now, behold, the king walketh before you: and I am old and grayheaded; and, behold, my sons are with you: and I have walked before you from my childhood unto this day.

But Saul said to David, "You will not be able to go against this Philistine to fight with him, because you are [only] a boy, whereas [he has] been a man of war since his childhood!"