Something forbidden by the Prophet ﷺ is legally prohibited

Narrated Ata:

I heard Jabir bin 'Abdullah in a gathering saying, "We, the companions of Allah's Apostle assumed the state of Ihram to perform only Hajj without 'Umra." Jabir added, "The Prophet arrived (at Mecca) on the fourth of Dhul-Hijja. And when we arrived (in Mecca) the Prophet ordered us to finish the state of Ihram, saying, "Finish your lhram and go to your wives (for sexual relation)." Jabir added, "The Prophet did not oblige us (to go to our wives) but he only made that legal for us. Then he heard that we were saying, "When there remains only five days between us and the Day of Arafat he orders us to finish our Ihram by sleeping with our wives in which case we will proceed to 'Arafat with our male organs dribbling with semen?' (Jabir pointed out with his hand illustrating what he was saying). Allah's Apostle stood up and said, 'You (People) know that I am the most Allah-fearing, the most truthful and the best doer of good deeds (pious) from among you. If I had not brought the Hadi with me, I would have finished my Ihram as you will do, so finish your Ihram. If I had formerly known what I came to know lately, I would not have brought the Hadi with me.' So we finished our Ihram and listened to the Prophet and obeyed him." (See Hadith No. 713, Vol. 2)

حَدَّثَنَا الْمَكِّيُّ بْنُ إِبْرَاهِيمَ، عَنِ ابْنِ جُرَيْجٍ، قَالَ عَطَاءٌ قَالَ جَابِرٌ. قَالَ أَبُو عَبْدِ اللَّهِ وَقَالَ مُحَمَّدُ بْنُ بَكْرٍ حَدَّثَنَا ابْنُ جُرَيْجٍ، قَالَ أَخْبَرَنِي عَطَاءٌ، سَمِعْتُ جَابِرَ بْنَ عَبْدِ اللَّهِ، فِي أُنَاسٍ مَعَهُ قَالَ أَهْلَلْنَا أَصْحَابَ رَسُولِ اللَّهِ ﷺ فِي الْحَجِّ خَالِصًا لَيْسَ مَعَهُ عُمْرَةٌ ـ قَالَ عَطَاءٌ قَالَ جَابِرٌ ـ فَقَدِمَ النَّبِيُّ ﷺ صُبْحَ رَابِعَةٍ مَضَتْ مِنْ ذِي الْحِجَّةِ فَلَمَّا قَدِمْنَا أَمَرَنَا النَّبِيُّ ﷺ أَنْ نَحِلَّ وَقَالَ " أَحِلُّوا وَأَصِيبُوا مِنَ النِّسَاءِ ". قَالَ عَطَاءٌ قَالَ جَابِرٌ وَلَمْ يَعْزِمْ عَلَيْهِمْ وَلَكِنْ أَحَلَّهُنَّ لَهُمْ فَبَلَغَهُ أَنَّا نَقُولُ لَمَّا لَمْ يَكُنْ بَيْنَنَا وَبَيْنَ عَرَفَةَ إِلاَّ خَمْسٌ أَمَرَنَا أَنْ نَحِلَّ إِلَى نِسَائِنَا فَنَأْتِي عَرَفَةَ تَقْطُرُ مَذَاكِيرُنَا الْمَذْىَ قَالَ وَيَقُولُ جَابِرٌ بِيَدِهِ هَكَذَا وَحَرَّكَهَا فَقَامَ رَسُولُ اللَّهِ ﷺ فَقَالَ " قَدْ عَلِمْتُمْ أَنِّي أَتْقَاكُمْ لِلَّهِ وَأَصْدَقُكُمْ وَأَبَرُّكُمْ وَلَوْلاَ هَدْيِي لَحَلَلْتُ كَمَا تَحِلُّونَ فَحِلُّوا فَلَوِ اسْتَقْبَلْتُ مِنْ أَمْرِي مَا اسْتَدْبَرْتُ مَا أَهْدَيْتُ ". فَحَلَلْنَا وَسَمِعْنَا وَأَطَعْنَا.