I told you before, that good works must flow from faith: and now I tell you, that the best way to be fruitful in them, is to be much in the exercise of the doctrine of justification by grace; and they both agree; for as faith animates to good works, so the doctrine of grace animates faith. Wherefore, the way to be rich in good works, it is to be rich in faith; and the way to be rich in faith is to be conscientiously affirming the doctrine of grace to others, and believing it ourselves.
First, To be constantly affirming it to others. Thus Paul tells Timothy, that if he put the brethren in mind of the truths of the gospel, he himself should not only be a good minister of Christ, but should be nourished up in the words of faith and of good doctrine (1 Tim 4:6). It is the ordinance of God, that Christians should be often asserting the things of God each to others; and that by their so doing they should edify one another (Heb 10:24, 25;1 Thess 5:11).
The doctrine of the gospel is like the dew and the small rain that distilleth upon the tender grass, wherewith it doth flourish, and is kept green (Deu 32:2). Christians are like the several flowers in a garden, that have upon each of them the dew of heaven, which being shaken with the wind, they let fall their dew at each other's roots, whereby they are jointly nourished, and become nourishers of one another. For Christians to commune savourly of God's matters one with another, it is as if they opened to each other's nostrils boxes of perfume.19 Saith Paul to the church at Rome, 'I long to see you, that I may impart unto you some spiritual gift, to the end ye may be established; that is, that I may be comforted together with you, by the mutual faith both of you and me' (Rom 1:11, 12). Christians should be often affirming the doctrine of grace, and justification by it, one to another.
Second, As they should be thus doing, so they should live in the power of it themselves; they should by faith suck and drink in this doctrine, as the good ground receiveth the rain; which being done, forthwith there is proclaimed good works. Paul to the Colossians saith thus, 'We give thanks to God and the Father of our Lord Jesus Christ, praying always for you, since we heard of your faith in Christ Jesus, and love to all the saints; for the hope which is laid up for you in heaven, whereof ye heard before in the word of the truth of the gospel, which is come unto you, as it is in all the world, and bringeth forth fruit, as it doth also in you.' But how long ago? Why, 'since the day ye heard it, [saith he,] and knew the grace of God in truth' (Col 1:3-6).
Apples and flowers are not made by the gardener; but are an effect of the planting and watering. Plant in the sinner good doctrine, and let it be watered with the word of grace; and as the effect of that, there is the fruits of holiness, and the end everlasting life (Rom 6:22).
Good doctrine is the doctrine of the gospel, which showeth to men, that God clotheth them with the righteousness of his Son freely, and maketh him with all his benefits over to them; by which free gift the sinner is made righteous before God; and because he is so, therefore there is infused a principle of grace into the heart, whereby it is both quickened, and bringing forth fruit (Rom 3:21-26; 1 Cor 1:30; 2 Cor 5:21; John 1:16).
Now then, seeing good works do flow from faith, and seeing faith is nourished by an affirming of the doctrine of the gospel, &c., take here these few considerations from the doctrine of the gospel, for the support of thy faith, that thou mayest be indeed fruitful and rich in good works.
Consider 1. The whole Bible was given for this very end, that thou shouldest both believe this doctrine, and live in the comfort and sweetness of it: 'For whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the Scriptures might have hope' (Rom 15:4; John 20:31).
Consider 2. That therefore every promise in the Bible is thine, to strengthen, quicken, and encourage thy heart in believing.
Consider 3. That there is nothing that thou dost, can so please God as believing; 'The Lord taketh pleasure in them that fear him, in those that hope in his mercy' (Psa 147:11). They please him, because they embrace his righteousness, &c.