To find your mission you have but to be faithful wherever God puts you for the present. The humbler things he gives in the earlier years are for your training, that you may be ready at length for the larger and particular service for which you were born. Do these smaller, humbler things well, and they will prove steps in the stairs up to the loftier height where your "mission" waits. To spurn these plainer duties and tasks, and to neglect them, is to miss your mission itself in the end, for there is no way to get to it but by these ladder-rounds of commonplace things which you disdain. You must build your own ladder day by day in the common fidelities.
Philippians 2:12-15: Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling. For it is God which worketh in you both to will and to do of his good pleasure. Do all things without murmurings and disputings: That ye may be blameless and harmless, the sons of God, without rebuke, in the midst of a crooked and perverse nation, among whom ye shine as lights in the world; (KJV)
1 Corinthians 3:1-11: And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ. I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able. For ye are yet carnal: for whereas there is among you envying, and strife, and divisions, are ye not carnal, and walk as men? For while one saith, I am of Paul; and another, I am of Apollos; are ye not carnal? Who then is Paul, and who is Apollos, but ministers by whom ye believed, even as the Lord gave to every man? I have planted, Apollos watered; but God gave the increase. So then neither is he that planteth any thing, neither he that watereth; but God that giveth the increase. Now he that planteth and he that watereth are one: and every man shall receive his own reward according to his own labour. For we are labourers together with God: ye are God's husbandry, ye are God's building. According to the grace of God which is given unto me, as a wise masterbuilder, I have laid the foundation, and another buildeth thereon. But let every man take heed how he buildeth thereupon. For other foundation can no man lay than that is laid, which is Jesus Christ. (KJV)