Owen again on meditating on the righteousness of Christ

Believers approve of and rejoice in this righteousness [of Christ] because it brings great peace and assurance to their souls. They remember what fears  they had before. But now 'being justified by faith, they have peace with God' (Rom 5.1). All is quiet and still. Not only is the storm over, but they are safely anchored in the harbour. They have abiding peace with God. So we have that wonderful description of Christ given to us in Isaiah (Isa 32.2). The soul, through Christ, is at perfect peace with God (Isa 26.3; Psa. 4.6-8). So the souls of believers glorify the Lord Christ because they can come boldly to God with confidence, peace, joy and assurance. They can call him Father. They can strengthen themselves in his love. They can walk in peace and live without fear. Once they ran from him for fear. Now they can approach him with love, joy and peace.

John Owen, Communion with God (Banner of Truth), p.142

Grace revealed in the righteousness of Christ - John Owen

When the righteousness of Christ is first revealed to a sinner as the only way to be accepted by God, he is amazed and full of wonder and rejoices greatly. So he heartily approves of this righteousness because it reveals the glory of the wisdom of God (1 Cor 1:21). He sees what darkness he was in. He looked into himself and found only sin, horror, fear and tremblings. He looked up and saw nothing but wrath, curses and vengeance. He saw that God was holy and righteous and that no unclean thing could abide with him. He saw that he was a poor, vile, unclean and sinful creature and he could not see how a holy God and a sinful creature could be reconciled. But in the righteousness of Christ, a world of wisdom is opened, dispelling all difficulties and darkness and revealing how reconciliation could actually happen (Rom 11.33; Col 2.3).

What grace is revealed in this righteousness of Christ! The sinner does not have to earn it. God everywhere assures us that this righteousness is of grace (Rom 11.6; Eph 2.7-9). It is given to us by grace. It is from the riches of grace and kindness that this righteousness has been provided. So believers rejoice in this righteousness because it is ours by grace only.

John Owen, Communion with God (Banner of Truth), pp.141-142

Owen on God's mercy

Pardoning mercy comes by Christ alone. This pardoning mercy is revealed in the gospel, and in this pardoning mercy God will be glorified for ever (Eph 1.6). Pardoning mercy is not a vague general mercy which overlooks sin. This would be dishonouring to God. Pardoning mercy is God's free, gracious acceptance of a sinner because satsifaction was made to his justice consistent with his glory. It is a mercy of inconceivable wonder, for God came down from the heights of glory to bring forgiveness to sinners, whilst at the same time exacting justice and severity on sin. 

John Owen Communion with God (Banner of Truth 1991), p.80

John Owen on grace

Grace is a word which has various meanings. But chiefly it means three things:

(1) Grace can mean grace of personal presence and beauty. So we say, 'He or she is a graceful and beautiful person'. The Song of Solomon deals mainly with the grace and beauty of Christ's person. See also Psalm 45.2

(2) Grace can mean grace of free favour and acceptance. 'By grace you are saved'. That is, we are saved by the free favour and merciful acceptance of God in Christ. So the expression 'If I have found grace in your sight' is often used. The person using this expression hopes that he will be freely and favourably accepted. So God 'gives grace', that is, favour, to the humble. (James 4.6; Gen. 39.21; 41.37; Acts 7.10; 1 Sam 2.26; 2 Kings 25.27)

(3) Grace can mean the fruit of the Spirit sanctifying and renewing our natures, enabling us to do those good things which God has purposed and planned for us to do, and holding us back from evil. 'My grace is sufficient for you,' says the Lord Christ. That is, the help which God gave was sufficient for Paul (2 Cor. 12.9; 8.6, 7; Col 3.16; Heb 12.28)

The last two meanings of the word grace, as relating to Christ, I call 'purchased grace', being purchased by him for us. And our communion with Jesus in this purchased grace is called 'a fellowship in his sufferings, and the power of his resurrection.' (Phil. 3.10)

John Owen, Communion with God (Banner of Truth, 1991), pp.46-47

John Owen on the importance of engaging the mind in the struggle against sin

Two quotes from Indwelling Sin chapter 9; worth chewing over.

The steadfastness of the minds abiding in their duty is the cause of all our unmovableness and fruitfulness in obedience;... For if the soul be safe, unless the mind be drawn off from its duty, the soundness and steadfastness of the mind is its great preservative. And there are three parts of this steadfastness of the mind: - First, a full purpose of cleaving to God in all things; secondly, A daily renovation and quickening of the heart unto a discharge of this purpose; thirdly, Resolutions against all the dalliances or parleys about negligences in that discharge.

there are some duties which, in their own nature and by God's appointment, have a peculiar influence into the weakening and subduing the whole law of sin in its very principles and chiefest strengths; and these the mind of a believer ought principally in his whole course to attend unto; and these doth sin in its deceit endeavor principally to draw off the mind from... Now, these duties are - first, Prayer, especially private prayer; and, secondly, Meditation.

For a brilliant book about fighting against sin that is much simpler than Owen, I highly recommend Kris Lungaard: The Enemy Within.