Halakhah zu Tehillim 55:17

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.”