The Great Canon of St Andrew of Crete is the longest canon in all of our services, and is associated with Great Lent, since the only times it is appointed to be read in church are the first four nights of Great Lent (Clean Monday through Clean Thursday, at Great Compline, when it is serialized) and at matins for Thursday of the fifth week of Great Lent, when it is read in its entirety.
There is no other sacred hymn which compares with this monumental work, which St Andrew, Bishop of Crete, wrote for his personal meditations. Nothing else has its extensive typology and mystical explanations of the scripture, from both the Old and New Testaments. . One can almost consider this hymn to be a “survey of the Old and New Testament”. It's other distinguishing features are a spirit of mournful humility, hope in God, and complex and beautiful Trinitarian Doxologies and hymns to the Theotokos in each Ode.