When God calls us to serve Him in some way, He doesn't promise that it will be easy. Sometimes, what He is calling us to do is something that takes us out of our comfort zone. Other times, it may be something that we don't feel equipped or qualified to do. And there may even be times it is something that we're not really willing to do.
Abram was called by God to be the father of a whole new nation of people. God called him out of his comfort zone. He told Abram to leave his country, his people, and even his family, and to travel to the land that God had promised him.. He was required to step out of what was familiar and comfortable and step into what was unknown and uncomfortable. Abram was given a promise of not just a new land, but a multitude of descendants. But to get there, he had to step out of his comfort zone and follow the path that God set before him (Genesis 12:1-4).
Moses was called by God to lead His people, the Israelites, out of the land of Egypt where they were enslaved. God told Moses that he would be the one to go to Pharaoh and set His people free. But Moses did not feel qualified to do this. He didn't feel equipped to do what God was telling him to do (Exodus 3:10-12).
When God directs us to a ministry, a mission, or some other form of service, He doesn't do so because we are fully equipped and qualified. He doesn't do it because He knows it is something that we feel very comfortable doing. He does it because He wants us to exercise our faith, to trust Him and rely on His strength. When we submit our will to His and step into what He is calling us to do, He will guide us on the path set before us (Proverbs 3:5-6). As Abram stepped out of His comfort zone, he was blessed by God every step of the way. As Moses traveled to Egypt to lead God's people out of slavery to Pharaoh, God gave him all that he needed to accomplish it.
God never promises that serving Him will be easy. All He asks of us is that we be strong, trust Him and rely on Him and not get discouraged. What He does promise is that He will be with us every step of the way (Joshua 1:9).