[Machine] Umar ascended the pulpit and praised Allah and glorified Him, then he said, "What is with these men who engage in temporary marriage (mut'ah) even though the Messenger of Allah ﷺ has forbidden it? Indeed, I do not punish anyone who engages in it except by stoning." If this narration is authentic, it would indicate that Umar (may Allah be pleased with him) only forbade mut'ah because he knew about the prohibition of the Prophet ﷺ on it.  

صَعِدَ عُمَرُ عَلَى الْمِنْبَرِ فَحَمِدَ اللهَ وَأَثْنَى عَلَيْهِ ثُمَّ قَالَ مَا بَالُ رِجَالٍ يَنْكِحُونَ هَذِهِ الْمُتْعَةَ وَقَدْ نَهَى رَسُولُ اللهِ ﷺ عَنْهَا أَلَا وَإِنِّي لَا أُوتَى بِأَحَدٍ نَكَحَهَا إِلَّا رَجَمْتُهُ فَهَذَا إِنْ صَحَّ يُبَيِّنُ أَنَّ عُمَرَ ؓ إِنَّمَا نَهَى عَنْ نِكَاحِ الْمُتْعَةِ لِأَنَّهُ عَلِمَ نَهْيَ النَّبِيِّ ﷺ عَنْهُ