Complex sentence: The third urges the faithful departed to join in praising God, including the church patriarchs, prophets, apostles, martyrs and saints, addressed in groups similar to those in the Litany of the Saints.
Split into simpler sentences: The third urges the saints to join in praising God and also urges the patriarchs, prophets, apostles, and martyrs to join. They are addressed in groups similar to those in the Litany of the Saints.