Preparation

David said to the Philistine, "You come against me with the sword and sword and spear and javelin, but I come against you in the name of the Lord Almighty, the God of the armies of Israel, whom you have defied. This day the Lord will hand you over to me...So David triumphed over the Philistine with a sling and a stone; without a sword in his hand he struck down the Philistine and killed him. ~ 1 Samuel 17:45-46, 50

There are many things in this world that come against us with the purpose to destroy us. The question of how we will deal with these forces is answered in two ways. 1) What has our "training" been like? "Train even your weaklings to be warriors," (Joel 3:10). All of us are trained for the things God has in store for us. It may not be equal to the formal education or parenting that others have received. But God does not follow man's rules for "training." In fact, when we are first introduced to David, who would later become king, his own father disregards him as one who tends sheep (see 1 Samuel 16:11). But God said, "Man looks at the outward appearance, but the Lord looks at the heart," (1 Samuel 16:7). Through shepherding, God had been training David for the things He would call Him to do later. For example, David had to keep a watchful eye out for many predators, and when the did come, he had to physically fight them off. He also had to know how to tend, feed, and care for the many in his flock. Even if it wasn't as glamorous as some, David still received all the training he would need to take the next step when God called him.
2) Who is fighting for us and with us? In 1 Samuel 17, David said tot he army of giants that he was not afraid of them because he knew he wasn't fighting alone. He said, "I come against you in the name of the Lord Almighty, the God of the armies of Israel," (v 45). When we fight the things that are against God and against His will for our lives, we do not fight alone. God never wanted us to feel helpless in the face of battle, so He described in detail our weapons of warfare (see Ephesians 6:10-20).

The bottom line is that when God calls you, He prepares, trains, and equips you and He never sends you out alone. Know that whatever you are facing, whatever you may be fighting, God is with you. Always.

The Lord himself goes before you and he will be with you; he will never leave you nor forsake you. Do not be afraid; do not be discouraged. ~ Deuteronomy 31:8