Explanation

• Hazrat Ishaq (A.S) was the second son of Hazrat Ibrahim (A.S).
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•  You can verify from Surah Shafaat, Ayat NO 101
• Ibraham had two children, Ishmael and Isaac, who both later became prophets.
• Ismail (A.S) from Hajra (A.S) and Ishaq (A.S) from Sara (A.S).
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 A related question to Hazrat Ibrahim (A.S):

•  Hazrat Ibrahim (A.S) was born Iraq
  
•  13 times Hazrat Ibrahim (علیہ) is mentioned in Sura Baqarah
• Hazrat Ibrahim (AH) name mentioned in the Holy Quran 69 times.
• Khalil Ullah is the title of Hazrat Ibrahim (A.S)
• Hazrat Hajirah the second wife of Hazrat Ibrahim (A.S)