What happens on judgment day to a believer who constantly criticizes others, blames everyone else for his problems, and refuses to forgive others by always bringing up their past wrongdoing?

I cannot say definitively what will happen on the Last Day to this constantly critical person because I cannot look into his heart. He may be a weak or immature believer reminiscent of the Corinthians with their habitually bad behavior (see 1 Corinthians 1:11; 3:1-3). Or he may be an unbeliever whose profession of faith is empty. But I can say that we all have to deal with critical people, even in the church, and important issues need to be identified and addressed whenever that happens.

I appreciate the fact that you are asking the question and expressing concern. It is not normal for believers to be so characteristically or chronically critical of others. We should not ignore, much less excuse, such behavior or take it lightly.

TAKE THIS SERIOUSLY

You describe a faultfinding lifestyle trait. This is disturbing. All of us have bad moments, are subject to bad moods, and can be critical at times. But the Bible describes a child of God as one whose dominant lifestyle is governed by the new man rather than the old. We're not talking about ethical perfection, but we are talking about a discernible habitual pattern of godly attitudes and actions, fueled and maintained by the Holy Spirit through the gospel. Constant depreciation of others and an unforgiving attitude are not compatible with true faith (as James 3:9-12 and Matthew 18:21-35 illustrate well). So we take this situation seriously.

Even if faith remains, denigrating others is not living a life "worthy of the calling [we] have received" (Ephesians 4:1). There may well be serious psychological and social issues to be addressed. Most often, as the old adage says, "hurting people hurt people." Low self-esteem and insecurity are frequently involved, and miserable people tend to prefer—or seek to create—miserable companions. Even if it's more of a superficial matter of lacking social skills like diplomacy and tact, this is serious stuff for the Christian community, since we represent our Lord when we interact with others.

TAKE TIME TO SERVE