Translation of the verse 86 from Surah Ash-Shu‘ara’ : Number of verses 227 - - page 371 - Part 19.
And forgive my father, verily he is of the erring;
And forgive my father. Indeed, he has been of those astray.
(26:86) and forgive my father, for indeed he is from among those who have strayed, *63 ;
*63) Some commentators have interpreted this prayer of Prophet Abraham for his father's forgiveness to imply that he had prayed to God to grant his father the favour to accept Islam because forgiveness in any case is inter-linked with and dependent upon Faith. But this interpretation is not borne out by the other verses of the Qur'an. The Qur'an says that when Prophet Abraham left his home at the tyrannical treatment of his father, he said, "I bid farewell to you; I shall pray to my Lord to forgive you for He is very kind to me." (Maryam: 47) To fulfill this promise, he not only prayed for the forgiveness of his father, but for both his parents: "Lord, forgive me and my parents..." (Ibrahim: 41). But afterwards he himself realized that an enemy of the Truth, even if he be the father of a believer, does not deserve a prayer of forgiveness. Thus according to verse 114 of AtTaubah: "The prayer of Abraham for his father was only to fulfil a promise he had made to him, but when he realized that he was an enemy of Allah, he disowned him."
Source : Ash-Shu‘ara’ Verse 86: And forgive my father. Indeed, he has been of those astray.