Muwatta Malik, Book 15, Hadith 514 (In-Book)

Yahya related to me from Malik that he had heard that Abdullah ibn Umar said, "O Allah, make me one of the leaders of the people of taqwa." Allahumma jalniy min a'imati'l-mutaqin.

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، قَالَ اللَّهُمَّ اجْعَلْنِي مِنْ أَئِمَّةِ الْمُتَّقِينَ ‏.‏

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also referenced under: Book 15, Hadith 42 (USC-MSA)