Over the last several years, I've noticed something about people in the Bible. It seems to me that there is some foreshadowing of their calling at an early age.
Moses "Out of the Water"
Take Moses for instance, in Exodus 2:10, "When the child grew older, she took him to Pharaoh's daughter and he became her son. She named him Moses, saying, "I drew him out of the water." Later, as we all know, Moses was used of God to part the sea. He parted the Red Sea and took the people of God safely through. He truly was a man God used "out of the water."
Joseph the "Dreamer"
Two things stood out about Joseph in his early life: he was favored by his father over his brothers, because he was the oldest son of Jacob's favorite wife Rachel (Genesis 37:3). And Joseph was also known to his family for his crazy dreams (Genesis 37:5).
His brothers were so jealous of him that one day while working out in the fields, they sold him as a slave. It seems that everywhere he went as a slave and a prison inmate, the favor of God was with him, promoting him above the rest.
And, of course, the dreams. While in prison we find that God had gifted Joseph, not only to dream dreams, but also to interpret them (Genesis 40). Later, he interpreted very important dreams for Pharaoh, King of Egypt and ruler of the world at that time, and was exalted to second in command of the Kingdom.
David "Giant Killer"
David killed Goliath, and later dozens of people who followed him became fierce warriors and giant killers (2 Samuel 23).
Even David, facing Goliath that day, could look back and remember when God was with him to kill a lion and a bear in his youth!
What Has God Done in Your Past that Points To Your Future?
This is not a cure-all solution for the purposes of God in our lives, but it may give us clarity, as we "see things again for the first time," and notice what God has done in our past, that could be leading toward His purposes for our future.