6:88
ذَٰلِكَ هُدَى ٱللَّهِ يَهْدِى بِهِۦ مَن يَشَآءُ مِنْ عِبَادِهِۦ ۚ وَلَوْ أَشْرَكُوا۟ لَحَبِطَ عَنْهُم مَّا كَانُوا۟ يَعْمَلُونَ
That is the guidance of Allah by which He guides whomever He wills of His servants. But if they had associated others with Allah, then worthless for them would be whatever they were doing.
Translation · Saheeh International
Tafsir
Ibn Kathīr (abridged)
Ibrahim Receives the News of Ishaq and Ya`qub During His Old Age
Allah states that after Ibrahim became old and he, and his wife, Sarah, lost hope of having children, He gave them Ishaq. The angels came to Ibrahim on their way to the people of Prophet Lut (to destroy them) and they delivered the good news of a child to Ibrahim and his wife. Ibrahim's wife was amazed at the news,
قَالَتْ يوَيْلَتَا ءَأَلِدُ وَأَنَاْ عَجُوزٌ وَهَـذَا بَعْلِى شَيْخًا إِنَّ هَـذَا لَشَىْءٌ عَجِيبٌ - قَالُواْ أَتَعْجَبِينَ مِنْ أَمْرِ اللَّهِ رَحْمَتُ اللَّهِ وَبَرَكَـتُهُ عَلَيْكُمْ أَهْلَ الْبَيْتِ إِنَّهُ حَمِيدٌ مَّجِيدٌ
(She said (in astonishment): "Woe unto me! Shall I bear a child while I am an old woman, and here is my husband, an old man Verily! This is a strange thing!" They said: "Do you wonder at the decree of Allah The mercy of Allah and His blessings be on you, O the family of Ibrahim. Surely, He (Allah) is All-Praiseworthy, All-Glorious.") 11:72-73 The angels also gave them the good news that Ishaq will be a Prophet and that he will have offspring of his own. In another Ayah, Allah said;
وَبَشَّرْنَـهُ بِإِسْحَـقَ نَبِيّاً مِّنَ الصَّـلِحِينَ
(And We gave him the good news of Ishaq a Prophet from the righteous.)37:112, which perfects this good news and completes the favor. Allah said,