Sunan Ibn Majah, Volume 4, Book 24, Hadith 2826 (DarusSalam) ⓘ
It was narrated that Ibn ‘Umar said: “When the Messenger of Allah would dispatch troops, he would say to the leader: ‘I commend to Allah’s keeping your religious commitment, your dignity and the end of your deeds.’”
حَدَّثَنَا عَبَّادُ بْنُ الْوَلِيدِ، حَدَّثَنَا حَبَّانُ بْنُ هِلاَلٍ، حَدَّثَنَا أَبُو مِحْصَنٍ، عَنِ ابْنِ أَبِي لَيْلَى، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا أَشْخَصَ السَّرَايَا يَقُولُ لِلشَّاخِصِ " أَسْتَوْدِعُ اللَّهَ دِينَكَ وَأَمَانَتَكَ وَخَوَاتِيمَ عَمَلِكَ " .
also referenced under: Hadith 2826 (Reference) & Book 24, Hadith 2933 (In-Book)