Muwatta Malik, Book 20, Hadith 914 (In-Book)

Yahya related to me from Malik that Nafi said, "They say that Umar ibn al-Khattab used to send men out to bring people in from beyond al-Aqaba."

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّهُ قَالَ زَعَمُوا أَنَّ عُمَرَ بْنَ الْخَطَّابِ، كَانَ يَبْعَثُ رِجَالاً يُدْخِلُونَ النَّاسَ مِنْ وَرَاءِ الْعَقَبَةِ ‏.‏

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also referenced under: Book 20, Hadith 217 (USC-MSA)