Romans 12:3, 6 When we read Romans 12:6, we can notice first of all, that any spiritual gift we have from God, is all to do with his grace, and the particular grace for just that one gift, you have received from God. I think, it is possible that God gives a different amount or level of grace to different people, in order to enable them to function, in a particular spiritual gift.
You see, the Bible also says that God has given each of us, a measure of faith, in Romans 12:3. A measure of faith given from God to us, implies a measure of grace, or amount of grace, because we all have been given faith from God, once we became born again Christians. What does that mean?
Well, it means that to some of us, more grace is given from God, and to others less. The reason of why God gives more grace to certain individuals is, because there is a particular spiritual gifts, which God has given that individual, but in order for that individual to operate properly in that gift, he or she has to have the amount of grace given by God, to that individual.
It is no surprise then, to see some people whom God has called into ministry, to operate in a particular spiritual gift like healing or prophecy, and in a way that is very effective, and we wonder why we can not operate like them.
But look, for a particular reason, which God only knows, when God has called that person into ministry, he has also given them the amount, and that specific grace, that enables them to operate in that spiritual gifts. God is the giver of that gift, and God is the one determining how much grace to give to that person, operating in that spiritual gift. God determines that all, according to his choice and will, and for his glory.