From St Augustine:
We pray to Christ as God, and He prays for us as a servant. In the first case He is the Creator, in the second a creature. Himself unchanged, He took to Himself our created nature in order to change it, and He made us one man with Himself, Head and Body.
We pray then to Him, through Him, and in Him. We speak along with Him, and He speaks along with us. - Commentary on Psalm 85,1