“First of all every holy rite begins with the doxology: ‘Blessed is the kingdom of the Father, and of the Son and of the Holy Spirit.’ Intercourse with God consists of thanksgiving, doxology, confession, and petition. The first of these is doxology, because when grateful servants approach their Master it is fitting that they should begin not by pushing their own affairs into the foreground, but should concentrate on those of their Master. Such is the nature of doxology.
In petitioning we have in mind the advancement of our own interests. In confession we seek to be delivered from evils, and accuse ourselves. In giving thanks we clearly rejoice in the good things which we enjoy. But in doxology we lay aside ourselves and all our interests and glorify the Lord for his own sake, for his power and his glory. And so the very nature and the appropriateness of the act demand that the doxology should come first. Immediately we approach God we recognize the inaccessibility and force and grandeur of his glory, and are filled with wonder and awe and similar feelings. This is indeed doxology. We go on to recognize this goodness and love for mankind, and this gives rise to thanksgiving.
Then we consider his exceeding goodness and the liberality of his love for mankind, counting our own wickedness as the first and sufficient proof of that generosity and liberality, for whatever our shortcomings he continues to crown us with blessings. This is something which is near at hand within us, before our very eyes, and it proves to us more than anything else how much God loves mankind. And so we remember our sins before God, and this is called confession. The fourth element is petition. It follows that we can be confident that our requests for our needs will be granted, for we have just learned something of God’s goodness and his love for mankind.
He who has been good to those who were still sinners will surely be more so to those who have repented, and have become righteous by avowing their sins, according to the words of the prophet: ‘First confess yours sins in order that you may be justified.” (St Nicholas Cabasilas, A COMMENTARY ON THE DIVINE LITURGY, pp 43-44)