Halakhah su Salmi 55:78

Once the patriarchs invented these prayers, there were devout and righteous people who followed in their path and prayed Shaḥarit, Minḥa, and Ma’ariv. As King David said (Tehilim 55:17–18), “As for me, I call out to God, and the Lord saves me. Evening, morning, and noon, I express my grief and moan aloud, and He hears my voice.”

You should make a serious effort to pray with a congregation, as it is written; "As for me, may my prayer to You Hashem be at a favorable time."¹³Psalms 69:14. When is the time favorable? When the congregation prays together. It is [also] written: "Thus said Hashem; at a favorable time I have answered you."¹⁴Isaiah 49:8. The Holy One blessed is He never disdains the prayer of the multitude even though there are sinners in their midst, as it is written: "Behold, Hashem is mighty, (meaning He is the God of the multitude) yet He does not despise anyone."¹⁵Job 36:5. In Hebrew, kabbir also means many. It is [also] written: "He has redeemed my soul in peace from impending battle for the sake of the many that were with me."¹⁶Psalms 55:19.

Thus the poet (David) said, “Evening, morning, and noon” (Psalms 55:18), and he did not say “morning, noon, and evening”. He mentioned the three times when a person is obliged to pray, for the other(?) time people are asleep. That is “At midnight I arise to praise You” (ibid. 119:62).