I know of a minister who read from Psalm 23 at the graveside of a man who had lived an openly ungodly life. He read the psalm in the negative. "The Lord was not his shepherd, he will be in want, he will not lie down in green pastures, the Lord will not restore his soul." I'm not sure if I would have had the guts to do that. This is the force of Jesus' words in John 10. "You are not my sheep, I have not called you, I have not given you eternal life."
Calvin says of these verses:
Believers should...reckon that they are the more strongly bound to God because while others remain in blindness they are drawn to Christ by the enlightening of the Spirit. This is also a comfort to ministers of the gospel if their labour is not profitable to all.
It is is no small consolation to godly teachers that, although the larger part of the world does not listen to Christ, he has his sheep whom he knows and by whom he is also known. They must do their utmost to bring the whole world into Christ's fold, but when they do not succeed as they would wish, they must be satisfied with the single thought that those who are sheep will be collected together by their work.