The Work and the Works of Grace

Please read Ephesians 2:4-10
Paul closes this passage with a great exposition of that paradox which always lies at the heart of his view of the gospel. That paradox has two arms.
(i) Paul insists that it is by grace that we are saved. We have not earned salvation nor could we have earned it. It is the gift of God and our part is simply to accept it (put our faith in it alone). Paul's point of view is undeniably true; and for two reasons.
(a) God is perfection; and, therefore, only perfection is good enough for Him. Man by his very nature cannot bring perfection to God; and so, if ever man is to win his way to God, it must always be God who gives and man who takes.
(b) God is love; sin is therefore a crime, not against law, but against love. Now it is possible to make atonement for a broken law, but it is impossible to make atonement for a broken heart; and sin is not so much breaking God's law as it is breaking God's heart.
Let us take a crude and imperfect analogy. Suppose a motorist by careless driving kills a child. He is arrested, tried, found guilty, sentenced to a term of imprisonment and/or to a fine. After he has paid the fine and served the imprisonment, as far as the law is concerned, the whole matter is over. But it is very different in relation to the mother whose child he killed. He can never put things right with her by serving a term of imprisonment and paying a fine. The only thing which can restore his relationship to her is an act of free forgiveness on her part.
That is the way we are to God. It is not God's laws against which we have sinned; it is against His heart. And therefore only an act of free forgiveness of the grace of God can put us back into the right relationship with Him.
(ii) That is to say that works have nothing to do with earning salvation. It is neither right nor possible to leave the teaching of Paul here - and yet that is where it is so often left. Paul goes on to say that we are recreated by God for good works. Here is the Pauline paradox. All the good works in the world cannot put us right with God; but there is something radically wrong with the Christianity which does not issue in good works.
There is nothing mysterious about this. It is simply an inevitable law of love. If someone fine loves us, we know that we do not and cannot deserve that love. At the same time we know with utter conviction that we must spend all life in trying to be worthy of it.
That is our relationship to God. Good works can never earn salvation; but there is something radically wrong if salvation does not produce good works. It is not that our good works put God in our debt; rather that God's love lays on us the obligation to try throughout all life to be worthy of it.
We know what God wants us to do; God has prepared long beforehand the kind of life He wants us to live, and has told us about it in His book and through His Son, our perfect example. We cannot earn God's love but we can and must show how grateful we are for it, by seeking with our whole hearts to live the kind of life which will bring joy to God's heart.
--This is from William Barclay's book on the letters to the Galatians and Ephesians