بَارَكَ اللَّهُ لَكَ وَبَارَكَ عَلَيْكَ وَجَمَعَ بَيْنَكُمَا فِي خَيْرٍ
Barakallahu laka wa baraka 'alayka wa jama'a baynakuma fi khayr
May Allah bless you and shower His blessings upon you, and bring you both together in goodness.
This is the Sunnah way to congratulate newlyweds. The Prophet ﷺ taught this instead of the pre-Islamic congratulation which focused on worldly wishes. This du'a focuses on barakah (divine blessing) and goodness in the union.
Related Du'as
رَبَّنَا أَفْرِغْ عَلَيْنَا صَبْرًا وَتَوَفَّنَا مُسْلِمِينَ
Our Lord, pour upon us patience and let us die as Muslims.
Sahihاللَّهُمَّ اجْعَلْ بَيْنَنَا مَوَدَّةً وَرَحْمَةً وَسَكِينَةً، وَأَلِّفْ بَيْنَ قُلُوبِنَا وَاجْعَلْنَا قُرَّةَ أَعْيُنٍ لِبَعْضِنَا
O Allah, place between us affection, mercy, and tranquility. Unite our hearts and make us the coolness of each other's eyes.
Sahihاللَّهُمَّ إِنِّي أَسْأَلُكَ حُبَّكَ وَحُبَّ مَنْ يُحِبُّكَ وَحُبَّ كُلِّ عَمَلٍ يُقَرِّبُنِي إِلَى حُبِّكَ
O Allah, I ask You for Your love, the love of those who love You, and the love of every deed that brings me closer to Your love.
Hasanبِسْمِ اللَّهِ اللَّهُمَّ جَنِّبْنَا الشَّيْطَانَ وَجَنِّبِ الشَّيْطَانَ مَا رَزَقْتَنَا
In the Name of Allah. O Allah, keep Shaytan away from us and keep Shaytan away from what You bless us with.
Sahih