Explanation of the hadith
The Prophet (may Allah's peace and blessings be upon him) clarified that the prayer is invalid without reciting Surat al-Fātihah, which is one of the pillars of prayer in every Rak‘ah (unit of prayer).
عَنْ عُبَادَةَ بْنِ الصَّامِتِ رضي الله عنه أَنَّ رَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ:
عَنْ عُبَادَةَ بْنِ الصَّامِتِ رضي الله عنه أَنَّ رَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ: «لَا صَلَاةَ لِمَنْ لَمْ يَقْرَأْ بِفَاتِحَةِ الكِتَابِ».
‘Ubādah ibn as-Sāmit (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said:
‘Ubādah ibn as-Sāmit (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "The prayer of the one who did not recite the Opening of the Book (Surat al-Fātihah) is invalid."
The Prophet (may Allah's peace and blessings be upon him) clarified that the prayer is invalid without reciting Surat al-Fātihah, which is one of the pillars of prayer in every Rak‘ah (unit of prayer).