Some of the evidence that it is obligatory to pray in congregation
It was narrated from Abū Hurayrah (may Allāh be pleased with him) that he said, “A blind man came to the Prophet (May Allāh praise him and Peace be upon him) and said, “O Messenger of Allāh, I have nobody to lead me to the mosque.” So, he asked for permission to pray at home. So, he gave him permission. Then, as the man turned away, the Prophet (May Allāh praise him and Peace be upon him) called him and said, “Do you hear the call to prayer?” He answered, “Yes,” then the Prophet (May Allāh praise him and Peace be upon him) said, “In that case, answer it.” [Ṣaḥīḥ Muslim 653].
It was narrated from Ibn ‘Abbās (may Allāh be pleased with him) that he Prophet (May Allāh praise him and Peace be upon him) said “If somebody hears the call to prayer and does not attend, then he has not prayed, unless he has an excuse” [Al-Irwā` 2/237].
It was narrated from Abū Hurayrah (may Allāh be pleased with him) that the Prophet (May Allāh praise him and Peace be upon him) said “By The One in Whose Hand is my soul, I was about to order for firewood to be collected and burnt and then order someone to pronounce the adhān for the prayer and then order someone to lead the prayer. Then I would go from behind the houses of men who did not attend and burn them. By He in Whose Hand is my soul, if anyone of them had known that he would get a bone covered with good meat or two nice little pieces of meat between two ribs, he would have attended the ‘Ishā` (night-time) prayer.” [Bukhārī: 644]
It was narrated from Abū Al Dardā’ (May Allāh be pleased with him) that the Prophet (May Allāh praise him and Peace be upon him) said “If ever three people whether in town or in the desert make no arrangement to pray in congregation, Shayṭān (Satan) will get the better of them. So, remain firmly attached to the congregation and the body of Muslims, because the wolf only eats the lone sheep that strays from the flock” [Ṣaḥīḥ Sunan Abī Dāwūd: 511].