RIchard SIbbes 4

... Holy St Paul laboured to keep a good conscience in all things. 

Herein I exercise myself, to have a good conscience towards God and men, etc Acts 24:16.

It is easy for him to desire to be dissolved, that hath his conscience sprinkled with the blood of Christ, Heb 10:22, free from a purpose of living in any sin. But where there is a stained, defiled, polluted conscience, there cannot be this desire; for the heart of man, naturally, as the prophet saith, casts up mire and dirt Isa 57:20. It casts up fears, and objections, and murmurings, and repinings. Oh, beloved, we think not what mischief sin will do us, when we suffer it to seize upon our consciences; when it is once written there with the claw of a diamond, and with a pen of iron, Jer 17:1, who shall get it out? Nothing but great repentance and faith, applying the blood of Christ. It is no easy matter to get it off there, and to get the conscience at peace again; and when conscience is not appeased, there will be all clamours within. It will fear to appear before the judgment-seat. A guilty conscience trembles at the mention of death. Therefore I wonder how men that live in swearing in looseness, in filthiness, in debauchery of life, that labour to satisfy their lusts and corruptions, I wonder how they can think of death without trembling, considering that they are under the guilt of so many sins. Oh, beloved, the exercising of the heart to keep a clear conscience, can only breed this desire in us to depart, and to be with Christ. You have a company of wretched persons, proud enough in their own conceits, and censorious. Nothing can please them, whose whole life is acted by Satan joining with the lusts of their flesh, and they do nothing but put stings into death every day, and arm death against themselves, which when once it appears, their conscience, which is a hell within them, is wakened, and where are they? They can stay here no longer; they must appear before the dreadful Judge; and then where are all their pleasures and contentments, for which they neglected heaven and happiness, peace of conscience, and all? Oh, therefore let us walk holily with our God, and maintain inward peace all we can, if we desire to depart hence with comfort.

Richard Sibbes 3

What is our life without joy? Without joy we can do nothing. We are like an instrument out of tune. An instrument out of tune it yields but harsh music. Without joy we are as a member out of joint. We can do nothing well without joy, and a good conscience, which is the ground of joy. A man without joy is a palsy-member that moves itself unfitly, and uncomely. He goes not about things as he should. A good conscience breeds joy and comfort. It enables a man to do all things comely in the sight of God, and comfortably to himself. It makes him go cheerfully through his business. A good conscience is a continual feast Prov. xv. 15. Without joy we cannot suffer afflictions. We cannot die well without it.

In his Commentary on 2 Corinthians 1:12

Richard Sibbes 1

Conscience is an inferior light of the Spirit: to do things against conscience is to do them against the Spirit. God spake to me, and I heeded him not. How doth God speak? When conscience speaks, and saith, This is good, this is bad, then God speaks. Conscience hath somewhat divine in it. It is a petty god. It speaks from God. Especially when the Spirit joins with conscience, then God speaks indeed; then there is light upon light.

From Works, A Fountain Sealed