Jeremiah was born a son of a priest but called to be a prophet at a young age, probably in his late teens or early twenties. However, God has prepared him to be a prophet long before he was called -- from his birth: "Before I formed you in the womb I knew you, before you were born I set you apart; I appointed you as a prophet to the nations." When God calls us to a specific ministry, He has already prepared us from the day we were born, even long before we knew Him. He decided who our parents were, where we would be born, and the kind of early childhood experience and education we would receive. He probably even determined the kind of personality type we would be born with! And all these for a reason -- that we might be appointed to that ministry work He has prepared beforehand for us to do.
We only have a ministry on the basis of God's calling. Even though Jeremiah was brought up in a priestly family and therefore destined to be a priest in his regular work, yet he was set apart for a specific call to be God's spokesperson in the critical juncture of Judah's history -- from the begining of decline (after Josiah) to Jerusalem's complete destruction and deportation of its people to Babylon. This spans over a period of more than 40 years, from 640-586 BC.
Some of us like Jeremiah may have regular work in life as home-maker, office worker, school teacher, business-person, civil servant, etc, but nevertheless, God has prepared us for a specific kingdom task that is based on the spiritual gift He has given us in Christ. While serving in our regular work, God have set us apart for a specific ministry based on our spiritual gift.
God's call is always based on His agenda, never ours. Jeremiah did not think he was called to be a public speaker, but God has a agenda for him--namely to convey God's message to a people destined for destruction. It was not a positive message Jeremiah was asked to bring to his people. It was a message of impending doom and destruction:
Jer 1:14-16 The Lord said to me, "From the north disaster will be poured out on all who live in the land. I am about to summon all the peoples of the northern kingdoms," declares the Lord. "Their kings will come and set up their thrones in the entrance of the gates of Jerusalem; they will come against all her surrounding walls and against all the towns of Judah. I will pronounce my judgments on my people because of their wickedness in forsaking me, in burning incense to other gods and in worshiping what their hands have made."
Jeremiah was called to be a preacher of Bad News because God needed someone to communicate that message for Him. Jeremiah would probably prefer to be a preacher of Good News. But God has called him to be a prophet, not an evangelist.
Each us have been prepared for a specific calling to fulfill God's agenda for our lives. It doesn't matter if we like the ministry or are naturally inclined. If God has called us to a task, He will provide the grace to do it.
Father, thank You that You have set us apart even from our mothers' wombs, long before we even heard of You or knew You. May we be found fulfilling Your agenda for which You have prepared us for since the day we were born. Amen.