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اللَّهُمَّ اغْفِرْ لَهُ، اللَّهُمَّ ثَبِّتْهُ
Edition transliteration
Allaahum-maghfir lahu Allaahumma thabbithu
Meaning
O Allah, forgive him. O Allah, strengthen him
Source and references
Hisn al-Muslim, entry 164.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗