But a conscience can become wounded and weak (1Co_8:12), even defiled and corrupted (1Co 8:7) through our lies and hypocrisy, seared with a hot iron. (1Ti 4:2) Then it’s useless, corrupting everything about us (Tit 1:15); then we’re calling evil good and good evil. (Is 5:20)
We cleanse our conscience by continually recalibrating it with God’s Word (Ps 119:9), comparing its assessments with what God says instead of the world, thereby renewing our minds by persistently aligning our conscience with revealed truth. (Ro 12:2) and allowing it time to adjust. At first, a weak conscience troubles us as we persist in obeying truth with our wills, just as it does when it’s clean and we’re offending against the truth, but it eventually heals and aligns with our will when our actions are according to truth.
God tells us to hold on to a good conscience, to protect and guard it (1Ti 1:19), to cleanse our evil conscience (He 10:22) from dead works through His blood. (He 9:14) He does this in us as we obey what we already know to be true (Ja 1:22), repenting of sin and walking according to all the truth we have (He 13:18), consistently delivering ourselves from bondage unto more and more freedom (2Ti 2:25), and ever seeking more truth (Ps 119:30), wisdom and understanding. (Pr 4:7)