The Prophet said: "The best of charity is when a Muslim man gains knowledge, then he teaches it to his Muslim brother."
أَنَّ النَّبِيَّ ﷺ قَالَ أَفْضَلُ الصَّدَقَةِ أَنْ يَتَعَلَّمَ الْمَرْءُ الْمُسْلِمُ عِلْمًا ثُمَّ يُعَلِّمَهُ أَخَاهُ الْمُسْلِمَ