In a letter written during his imprisonment in Rome, the Apostle Paul asked the Christian Jews to “Pray for us; for we are confident that we have a good conscience, in all things desiring to live honorably.” Hebrews 13:18
To a wicked Roman governor Paul wrote, “This being so, I myself always strive to have a conscience without offense toward God and men.” Acts 24:16
Human authorities that make laws to restrict religious liberty assume a right that belongs to God alone. (See The Desire of Ages, 630.) “The precepts of the Scriptures, conveyed through the understanding, are to rule the conscience; … God speaking in the Bible, and not the church speaking through the priesthood, is the one infallible guide.” The Great Controversy, 102
The way to have a good conscience is to become, by the grace of God, a holy person:
“The true Christian obtains an experience which brings holiness. He is without a spot of guilt upon the conscience or a taint of corruption upon the soul. The spirituality of the law of God, with its limiting principles, is brought into his life. The light of truth irradiates his understanding. A glow of perfect love for the Redeemer clears away the miasma which has interposed between his soul and God. The will of God has become his will, pure, elevated, refined, and sanctified. His countenance reveals the light of heaven. His body is a fit temple for the Holy Spirit. Holiness adorns his character. God can commune with him, for soul and body are in harmony with God.” The Seventh-day Adventist Bible Commentary, Vol. 7, 909
If we are to be ready for the Second Coming of Jesus, our conscience must be cleansed, just as the sanctuary had to be cleansed.
“For if the blood of bulls and goats and the ashes of a heifer, sprinkling the unclean, sanctifies for the purifying of the flesh, how much more shall the blood of Christ, who through the eternal Spirit offered Himself without spot to God, cleanse your conscience from dead works to serve the living God?” Hebrews 9:13, 14
“Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience and our bodies washed with pure water. Let us hold fast the confession of our hope without wavering, for He who promised is faithful.” Hebrews 10:22, 23