Unconfronted pride is a serious problem among believers. If one is struggling with an outward sin such as drinking, or drugs, or sexual perversion - they are more likely to be dealt with properly, than one who walks in persistent pride. It's a serious sin that's often treated as insignificant, or ignored altogether, despite it being the cause of Satan's condemnation (1 Timothy 3:6). But our God is greatly concerned with the state of our hearts; as it is written, "clean the inside of the cup first (Matthew 23:26)," and "guard your heart at all times (Proverbs 4:23)"
Moreover, to maintain a good conscience before God, we must confront (persistent) pride in our fellowship. We must deal with it first in ourselves, and then in anyone we fellowship with. For if left unchecked, it's like a spiritual cancer, that will bring corruption to the Body (Galatians 6:8) As it is written, "a little leaven leavens the whole lump"(Galatians 5:9), and "bad company corrupts good morals" (1 Corinthians 15:33).
And dealing with a prideful person is difficult, perhaps that's why we rather avoid correction. For they are often aggressive, manipulative and vindictive, but the righteous are as bold as lions. Therefore may God give us courage, wisdom and grace to confront them in a loving and biblical way. For God's will and the spiritual welfare of His people are at stake; so may we not be passive and complacent.