Bulugh al-Maram, Book 11, Hadith 1340 (English)

Al-Bukhari and Muslim transmitted in the hadith of Umm Hani’, “We have given protection to whom you have granted (protection).”

وَفِي "اَلصَّحِيحَيْنِ" مِنْ حَدِيثٍ أَمِ هَانِئٍ: { قَدْ أَجَرْنَا مَنْ أَجَرْتِ" } 1‏.‏ ‏1 ‏- صحيح.‏ وهو جزء من حديث رواه البخاري ( 3171 )‏، ومسلم ( ( 1 / 498 / رقم 82 )‏.‏

sunnah.com

also referenced under: Book 11, Hadith 1314 (In-Book)