Hadithcore
Mishkat al-Masabih, 730

He also reported God’s Messenger as saying, “If anyone comes to a mosque for a purpose, he will attain it.” Abu Dawud transmitted it.

وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ أَتَى الْمَسْجِدَ لِشَيْءٍ فَهُوَ حَظُّهُ» . رَوَاهُ أَبُو دَاوُد

References1 variant
In-Book Reference
Book 4, Hadith 159