Mishkat al-Masabih 19 Jihad كتاب الجهاد 30

وَعَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو قَالَ: جَاءَ رَجُلٌ إِلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَاسْتَأْذَنَهُ فِي الْجِهَادِ فَقَالَ: «أَحَي والدك؟» قَالَ: نَعَمْ قَالَ: «فَفِيهِمَا فَجَاهِدْ» . مُتَّفَقٌ عَلَيْهِ. وَفِي رِوَايَةٍ: «فَارْجِعْ إِلَى وَالِدَيْكَ فَأَحْسِنْ صُحْبَتَهُمَا»

‘Abdallah b. ‘Amr told that a man came to God’s Messenger and asked his permission to take part in jihad . He asked him if his parents were still alive, and when he replied that they were, he told him to exert himself* on their behalf. *The point is not so clear in English as in Arabic. Jihad , while being the word for fighting against infidels, also means to strive or to exert oneself in general. The man wished to take part in jihad , and when the Prophet heard that his parents were still alive he said fa-fihima fa-jahid (exert yourself on their behalf.) (Bukhari and Muslim.) A version has, “Return to your parents and look after them well.”