We join with you in lifting up this family member and their marriage before the Lord, for we know how heavy it is to watch someone we love suffer under destructive and selfish behavior within their own home.
We hear your heart crying out for them to get right with Jesus and that is the most important prayer we can pray, for apart from Christ there is no true change of heart. The behavior you describe as narcissistic is at its root pride and self-centeredness, which Scripture warns against. Proverbs 16:18 tells us pride goes before destruction, and a haughty spirit before a fall, and Philippians 2:3-4 calls us to do nothing from rivalry or conceit, but in humility count others more significant than ourselves, looking not only to our own interests but also to the interests of others. Destructive behavior flows from a heart that has not been humbled before God. We rebuke that spirit of pride and selfishness, for it harms the marriage covenant and wounds the whole family. At the same time we know that God is able to create a new heart. Ezekiel 36:26 promises I will give you a new heart, and I will put a new spirit within you, and 2 Corinthians 5:17 declares if anyone is in Christ, he is a new creation. The old things have passed away. Behold, all things have become new. What man cannot fix, God can transform when there is true repentance.
We believe marriage is a lifelong covenant between a man and a woman ordained by God, and Jesus said in Matthew 19:6 So that they are no more two, but one flesh. What therefore God has joined together, let no man separate. We pray for this marriage to be preserved and made holy, not by excusing sin but by both husband and wife being made right with Jesus and walking in obedience to Him. This means the one acting destructively must take ownership, confess and forsake that sin, for Proverbs 28:13 says he who conceals his sins will not prosper, but whoever confesses and forsakes them will obtain mercy, and 1 John 1:9 assures us if we confess our sins, he is faithful and righteous to forgive us the sins, and to cleanse us from all unrighteousness. Love in marriage is not enabling sin, and Scripture calls husbands to love their wives and not be bitter against them in Colossians 3:19 and to live with their wives with understanding and honor in 1 Peter 3:7, while all of us are called to let all bitterness, wrath, anger, outcry, and slander, be put away from you, with all malice in Ephesians 4:31 and to be kind to one another, tenderhearted, forgiving each other, just as God also in Christ forgave you in Ephesians 4:32.
We pray together now for them.
Father in heaven, we come before You in the name of Jesus Christ, Your Son, asking for Your mercy and power to move in this family. We lift up our family member and their spouse to You. Lord, draw them both into a right relationship with Jesus, for we know it is only through Him that we have access to You and that there is no other name under heaven by which we must be saved. We ask You to convict the heart that has been prideful and destructive, to bring deep godly sorrow that leads to repentance and to cleanse and renew that heart by Your Holy Spirit. Bring healing to the wounds that have been inflicted on this family, soften hearts that have grown hard, and restore trust where it has been broken. Help our family member to walk in wisdom, to speak the truth in love in Ephesians 4:15, to set godly boundaries while also extending forgiveness as You have forgiven us, and to not grow weary in doing good. We pray for godly counselors and pastors to come alongside this marriage, for protection over this family, and for Your peace to reign in their home. Let Your fruit of love, joy, peace, patience, kindness, goodness, faith, gentleness, and self-control in Galatians 5:22-23 be evident in both lives as they surrender to You. We ask that as far as it depends on them, they would live peaceably as Romans 12:18 teaches, and that this marriage would be strengthened to reflect Christ and His church and honor You all the days of their lives. In Jesus name we pray, amen.
We encourage you to continue to pray fervently, for James 5:16 reminds us the insistent prayer of a righteous person is powerfully effective. Keep pointing your family member to Jesus and to His Word, encourage them to seek wise biblical counsel from a pastor or mature believers and not to walk this road alone, and encourage both husband and wife, if willing, to humble themselves before the Lord together. God is faithful to hear our prayers and to work even in the most difficult situations for His glory and their good.