"And whatever strikes you of disaster - it is for what your hands have earned," meaning: for what your hands have wrought, "but He pardons much."
Muhammad said: Yahya read it as "fa-bima" (so for what), while the people of Medina read it as "bima" (for what) without the "fa".
﴿وَمَا أَصَابَكُم مِّن مُّصِيبَةٍ فَبِمَا كَسَبَتْ أَيْدِيكُمْ﴾ فبمَا عملت أَيْدِيكُم ﴿وَيَعْفُو عَن كَثِيرٍ﴾.
قَالَ محمدٌ: قَرَأَ يحيى ﴿فَبِمَا﴾ وَأهل الْمَدِينَة يقرءُون ﴿بِمَا﴾ بِغَيْر فَاء.
