Muwatta Malik #954
Hajj
The Arabic includes the chain of narration (sanad) and the collector's commentary; the English translation shows the Prophet's words only.
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّهُ قَالَ زَعَمُوا أَنَّ عُمَرَ بْنَ الْخَطَّابِ، كَانَ يَبْعَثُ رِجَالاً يُدْخِلُونَ النَّاسَ مِنْ وَرَاءِ الْعَقَبَةِ .
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."
About Muwatta Malik
This hadith is #954 from Muwatta Malik, in the Book of Hajj.