In 2 Timothy 1:9, we learn that God has saved us and called us with a holy calling. We are first called to salvation, then He calls us to serve Him. Our calling can mean making a drastic change (like leaving our home to be a missionary in another country) or being diligent to serve in our everyday lives (like teaching our children about the Lord or being a witness in the workplace).
There are numerous examples of God calling individuals in the Bible, and the responses range from resistance to complete surrender. In 1 Samuel 9, when God first called Saul to be king, Saul responded with disbelief and questions because he was a Benjamite, of the smallest of the tribes of Israel, and ... the least of all the families of the tribe of Benjamin (verse 21). However, Samuel assured him that God would be with him and admonished him to do as the occasion demands (1 Samuel 10:6-7).
We see a completely different response when God asks in Isaiah 6:8 "Whom shall I send, And who will go for Us?" Isaiah boldly responds, "Here am I, send me!"
When God calls you, how will you respond - with unbelief and resistance or with complete surrender?