When ye shall have done all those things which are commanded you, say, We are unprofitable servants.
I was reading Pilgrim's Progress the other night and Bunyan made use of this verse highlighting the unprofitability of our doing.
It reminded me of another verse.
It is the Spirit who gives life; the flesh profits nothing.
There is no gain to be accounted for in our efforts alone.
If God does not do something, anything, no profit will be produced.