“But God in his grace chose me even before I was born, and called me to serve him”. 

Gal 1:15 GNB 

Many great people have known God was calling them. Albert Schweitzer, growing up in the province of Alsace in northern France, was a learned man. He had a doctorate in Philosophy, and another one in New Testament studies. He was a highly skilled musician. He knew he had to spend his talented life serving people but could not determine who. Then one day he happened to glance at a green magazine in his college library. There was an article by Alfred Boegner, President of the Paris Missionary Society about the needs of the mission in the Congo. As he read it, Schweitzer knew that his search was over. God had spoken to him. He qualified in medicine and went to Africa to found a hospital which served those who had neither medicine nor Christianity. In fulfilment of his calling he toured Europe frequently to raise funds by presenting organ recitals to pay the bills at Lambarene hospital. 
Paul knew that on the road to Damascus, as Christ accosted him and prevented him from persecuting the Christian church, God was calling him to be an ambassador for the gospel of Jesus Christ. It even seemed that that had been his destiny all along – his whole upbringing and education pointed in this direction. And Christ had filled his heart with love. 
You too have been chosen by God in some way or other, even if it is not to some spectacular field of service. Gordon MacDonald told of a dry-cleaning shop in New York where the owner, by care, pleasantness and efficiency brought Christ into his business. Customers could tell the difference and asked why. 

Lord, help me to fulfil my calling.