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,

﴿بِإِسْحَـقَ وَمِن وَرَآءِ إِسْحَـقَ يَعْقُوبَ﴾

(of Ishaq, and after him, of Ya`qub...) ﴿11:71﴾, meaning, this child will have another child in your lifetime, so that your eyes are comforted by him, just as your eyes will be comforted by his father. Certainly, one becomes jubilant and joyous when he becomes a grandfather, because this means that his offspring will continue to exist. It was also expected that if an elderly couple had children, due to the child's weakness, he would have no offspring. This is why Allah delivered the good news of Ishaq and of his son Ya`qub, whose name literally means `multiplying and having offspring'. This was a reward for Ibrahim who left his people and migrated from their land so that he could worship Allah alone. Allah compensated Ibrahim with better than his people and tribe when He gave him righteous children of his own, who would follow his religion, so that his eyes would be comforted by them. In another Ayah, Allah said; a

﴿فَلَمَّا اعْتَزَلَهُمْ وَمَا يَعْبُدُونَ مِن دُونِ اللَّهِ وَهَبْنَا لَهُ إِسْحَـقَ وَيَعْقُوبَ وَكُلاًّ جَعَلْنَا نَبِيّاً ﴾

(So when he turned away from them and from those whom they worshipped besides Allah, We gave him Ishaq and Ya`qub, and each one of them We made a Prophet.) ﴿19:49﴾ Allah said here,

﴿وَوَهَبْنَا لَهُ إِسْحَـقَ وَيَعْقُوبَ كُلاًّ هَدَيْنَا﴾

(And We bestowed upon him Ishaq and Ya`qub, each of them We guided,) Allah said;

﴿وَنُوحاً هَدَيْنَا مِن قَبْلُ﴾

(and before him, We guided Nuh...) meaning, We guided Nuh before and gave him righteous offspring, just as We guided Ibrahim and gave him righteous children.