I came across an interesting little story in the book Worship, Community, and the Triune God of Grace.
The most well-known controversy in the early church is Arianism. Arius was a priest in the fourth century who came into conflict with the church because he denied that Jesus was divine. One of his arguments went like this: Jesus cannot be God because Jesus prays to God. He prays on the mountain, he prays at the last supper, he prays in Gesthemene, and he prays from the cross. What could be more obvious than the fact that Jesus cannot be God (who receives prayer) if he is a man (who offers prayer)?
Athanasius, who opposed Arius, responded, “Arius, you don’t understand the meaning of grace!”
Why did Athanasius immediately point to grace? James Torrance answers:
“The God to whom we pray and with whom we commune knows we want to pray, try to pray, but cannot pray. So God comes to us as man in Jesus Christ to stand in for us, pray for us, teach us to pray and lead our prayers. God in grace gives us what he seeks from us—a life of prayer—in giving us Jesus Christ and the Spirit. So Christ is very God, the God to whom we pray. And he is very man, the man who prays for us and with us.”
That is the nature of grace. Both the divine act and the human response are given to us in Christ, and we participate in what Christ has accomplished by faith.