God has a mission: He wants all people to choose Him as God. Everything is part of God's mission to bring all people into and deeper into a relationship with Him. Everything that happens occurs to direct people to God. Also, every person that lives exists to join God's mission. Unlike time, events, and nature, though, people have a choice of if they will join God's mission.
God gives every person the freedom to choose to work with or against Him. He does that by using everything under His command to teach people that they exist for the purpose of serving Him. For Moses that began as a bush on fire but not burning up. For Saul it was preceded by losing his father's donkeys. For others it starts with an active childhood imagination. For each individual, God uses what will draw his or her full attention so He can drive His message deep into the heart. Then God continues to use everything to clarify His specific, unique mission for that individual.
All people exist to be in a relationship with God and to bring others into that same relationship. God creates a unique way for each person to fill that role. Moses' unique mission was to lead people out of Egypt and communicate God's laws. Saul was supposed to be a king that obeyed God. Others are created to write stories that teach about God in a way even people who don't like God will read. God has purpose and a unique purpose for each person. Whether or not that purpose ever plays out, though, depends on if each person chooses to work with or against God. Moses finally decided to serve God and transformed into a strong example of humble obedience. Saul finally decided to serve himself and transformed into a disturbed failure.
The choice is this: serve God and fulfill His purpose for you or exist without purpose.