وَمَا كَانَ ٱسْتِغْفَارُ إِبْرَٰهِيمَ لِأَبِيهِ إِلَّا عَن مَّوْعِدَةٍ وَعَدَهَآ إِيَّاهُ فَلَمَّا تَبَيَّنَ لَهُۥٓ أَنَّهُۥ عَدُوٌّ لِّلَّهِ تَبَرَّأَ مِنْهُ ۚ إِنَّ إِبْرَٰهِيمَ لَأَوَّٰهٌ حَلِيمٌ
wamā kāna is'tigh'fāru ib'rāhīma li-abīhi illā ʿan mawʿidatin waʿadahā iyyāhu falammā tabayyana lahu annahu ʿaduwwun lillahi tabarra-a min'hu inna ib'rāhīma la-awwāhun ḥalīmun
Abraham asked forgiveness for his father because he had made a promise to him, but once he realized that his father was an enemy of God, he washed his hands of him. Abraham was tender-hearted and forbearing.
And Ibrâhîm’s (Abraham) invoking (of Allâh) for his father’s forgiveness was only because of a promise he [Ibrâhîm (Abraham)] had made to him (his father). But when it became clear to him [Ibrâhîm (Abraham)] that he (his father) is an enemy of Allâh, he dissociated himself from him. Verily Ibrâhîm (Abraham) was Awwah (one who invokes Allâh with humility, glorifies Him and remembers Him much) and was forbearing. (Tafsir Al-Qurtubî).