What is the ruling on praying voluntary prayers in congregation?

Question : Honorable Shaykh, what is the ruling on praying voluntary prayers in congregation, such as the Duha prayer?

Answer : Praying voluntary prayers in congregation is sometimes permissible, because the Prophet (peace and blessings be upon him) prayed in congregation with his Companions on some nights. Once, Abdullah ibn Abbas (may Allah be pleased with them both) prayed with him, and once Abdullah ibn Mas'ud prayed with him, and once Hudhayfah ibn al-Yaman prayed with him. Both of them complained about the length of the Prophet's (peace and blessings be upon him) prayer. As for Hudhayfah, he reported that the Prophet (peace and blessings be upon him) recited Surat al-Baqarah, Surat al-Nisa, and Surat Aal 'Imran; he did not pass a verse of warning without seeking refuge, nor a verse of mercy without asking for it. As for Abdullah ibn Mas'ud, he prayed with the Prophet (peace and blessings be upon him) one night, and the Prophet (peace and blessings be upon him) prolonged the standing. Abdullah ibn Mas'ud said, "I was on the verge of doing something bad." He was asked, "What was the bad thing you were on the verge of doing?" He said, "That I would sit down and leave him," and that was due to the length of his standing (peace and blessings be upon him).
As for Abdullah ibn Abbas (may Allah be pleased with them both), he stood to pray the night prayer with the Prophet (peace and blessings be upon him) on his left side, so the Prophet (peace and blessings be upon him) took his head and placed him on his right side. The conclusion is that there is no harm in praying some voluntary prayers in congregation, but this should not become a regular practice where every time they pray the recommended practice, they pray it in congregation, because