The word rendered here as a type of "servant" really signifies a bondservant which is a slave. The distinction is important for us, for this word is used several times in the second half of Romans 6, where Paul writes of our usefulness to God. What is the difference between a servant and a slave? A servant may serve another, but the ownership of the servant does not pass to his employer. A servant retains his own ownership. If he likes his employer he can serve him, but if he does not, he can give in his notice, quit and seek another master. Not so is it with the slave. He is not merely another man's servant; he is his possession! The master owns the slave. How did I become the slave of the Lord Jesus? On His part he bought me at the price of laying down his life and shedding His precious blood; and on my part I presented myself freely and completely to him as alive from the dead. Let us not overlook that second statement.
Today in the Church as Christ's body, by the rights of redemption I am God's property, but if I would choose to be of use to Him, them I must willingly give myself to Him totally. He will never ever force me or compel me. The un-crucified 'self' of the nominal Christian is much like that of the servant. He vacillates between serving two masters - Christ and Self. Not so with the slave, he knows that he has been bought by the Lord Jesus at a high price, he is sold out and his one aim is to express his master's will in all things - he can do no other. There is no room for self-will in those who so choose! The bottom line is that we are anointed by His Holy Spirit to express His Life!