What does the Bible say about an evil conscience?

According to Hebrews 10:19-23, an evil conscience is defined as one that lacks genuine faith and assurance in Christ. It is characterized by self-righteousness and attempts to satisfy God's demands through personal works, rather than recognizing the need for Christ's sacrifice. An evil conscience indicates that one is relying on their own merits, which leads to a severed relationship with God. The scripture urges believers to hold fast to their faith with a true heart, fully recognizing that only through the blood of Jesus can one's conscience be cleansed.