929. hadíth
وَ فِي خَبَرٍ آخَرَ: «مَنْ حَلَقَ رَأْسَهُ أَوْ نَتَفَ إِبْطَهُ نَاسِياً أَوْ سَاهِياً أَوْ جَاهِلاً فَلاَ شَيْءَ عَلَيْهِ ».
In another narration: "Whoever shaves their head or plucks their underarm hair out of forgetfulness, inattentiveness, or ignorance, there is nothing upon them (no penalty)."