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.
Consider 4. That all the withdrawings of God from thee, are not for the weakening, but for the trial of thy faith; and also, that whatever he suffers Satan, or thy own heart to do, it is not to weaken faith (Job 23:8-10; 1 Peter 1:7).
Consider 5. That believing is that which will keep in thy view the things of heaven and glory; and that at which the devil will be discouraged, sin weakened, and thy heart quickened and sweetened (Heb 11:27; James 4:7; 1 Peter 5:9; Eph 6:16; Rom 15:13).
Consider lastly, By believing, the lover of God is kept with warmth upon the heart, and that this will provoke thee continually to bless God for Christ, for grace, for faith, hope, and all these things, either in God, or thee, that doth accompany salvation (2 Cor 2:14; Psa 103:1-3).
Third, The doctrine of the forgiveness of sins received by faith, will make notable work in the heart of a sinner, to bring forth good works. But, Forasmuch as there is a body of death and sin in every one that hath the grace of God in this world; and because this body of death will be ever opposing that which is good, as the apostle saith (Rom 7:21), therefore take these few particulars further, for the suppressing that which will hinder a fruitful life.
1. Keep a continual watch over the wretchedness of thy own heart, not to be discouraged at the sight of thy vileness, but to prevent its wickedness; for that will labour either to hinder thee from doing good works, or else will hinder thee in the doing thereof; for evil is present with thee for both these purposes. Take heed then, that thou do not listen to that at any time, but deny, though with much struggling, the workings of sin to the contrary.