John 6:43

Jesus answered and said unto them, Murmur not among yourselves. No man can come to me except the Father that sent me draw him; and I will raise him up in the last day.

Those who find in this an irresistible and sovereign act of God in calling individual sinners find much more than is in it, for the very next verse tells exactly how the drawing is accomplished: "They shall all be taught of God." To suppose that God draws some and not others would be to suppose that God is partial and unjust (Acts 10:34). The murmurers in this passage had rejected the teaching of God relative to the lowliness of the Messiah, thus thwarting God's drawing of them unto himself. The fact of rejection by some does not nullify the promise; the ones who respond will still be raised up at the last day.