Compiled by Imam Muhammad al-Bukhari
حَدَّثَنِي عُمَرُ بْنُ حَفْصٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا الأَعْمَشُ، حَدَّثَنَا إِبْرَاهِيمُ التَّيْمِيُّ، عَنْ أَبِيهِ، عَنْ أَبِي ذَرٍّ ـ رضى الله عنه ـ قَالَ قُلْتُ يَا رَسُولَ اللَّهِ. أَىُّ مَسْجِدٍ وُضِعَ أَوَّلُ قَالَ " الْمَسْجِدُ الْحَرَامُ ". قُلْتُ ثُمَّ أَىٌّ قَالَ " ثُمَّ الْمَسْجِدُ الأَقْصَى ". قُلْتُ كَمْ كَانَ بَيْنَهُمَا قَالَ " أَرْبَعُونَ ". ثُمَّ قَالَ " حَيْثُمَا أَدْرَكَتْكَ الصَّلاَةُ فَصَلِّ، وَالأَرْضُ لَكَ مَسْجِدٌ ".
I said, "O Allah's Messenger (ﷺ)! Which mosque was built first?" He replied, "Al-Masjid-ul-Haram." I asked, "Which (was built) next?" He replied, "Al-Masjid-ul-Aqs-a (i.e. Jerusalem)." I asked, "What was the period in between them?" He replied, "Forty (years)." He then added, "Wherever the time for the prayer comes upon you, perform the prayer, for all the earth is a place of worshipping for you."