Hadithcore
Mishkat al-Masabih, 1994

Mu'adh b. Zuhra told that when the Prophet (ﷺ) broke his fast he said, “O God, for You I have fasted and with Your provision I have broken my fast.” Abu Dawud transmitted it in <i>mursal</i> form.

وَعَنْ مُعَاذٍ بْنِ زُهْرَةَ قَالَ: إِنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ إِذَا أَفْطَرَ قَالَ: «اللَّهُمَّ لَكَ صَمْتُ وَعَلَى رِزْقِكَ أَفْطَرْتُ» . رَوَاهُ أَبُو دَاوُد مُرْسلا

References1 variant
In-Book Reference
Book 7, Hadith 38