Sunan Ibn Majah, Book 5, Hadith 978 (In-Book) ⓘ
It was narrated from Umm Salamah that when the Prophet performed the Subh (morning prayer), while he said the Salam, he would say: ‘Allahumma inni as’aluka ‘ilman nafi’an, wa rizqan tayyiban, wa ‘amalan mutaqabbalan (O Allah, I ask You for beneficial knowledge, goodly provision and acceptable deeds).’”
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا شَبَابَةُ، حَدَّثَنَا شُعْبَةُ، عَنْ مُوسَى بْنِ أَبِي عَائِشَةَ، عَنْ مَوْلًى، لأُمِّ سَلَمَةَ عَنْ أُمِّ سَلَمَةَ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ كَانَ يَقُولُ إِذَا صَلَّى الصُّبْحَ حِينَ يُسَلِّمُ " اللَّهُمَّ إِنِّي أَسْأَلُكَ عِلْمًا نَافِعًا وَرِزْقًا طَيِّبًا وَعَمَلاً مُتَقَبَّلاً " .
also referenced under: Hadith 925 (Reference) & Volume 2, Book 5, Hadith 925 (DarusSalam)