Hilary of Poitiers — as excerpted in the Catena Aurea on Matthew 1:16

“(Quæst. Nov. et Vet. Test. q. 49.) What God conveyed by the anointing of oil to those who were anointed to be kings, this the Holy Spirit conveyed upon the man Christ, adding thereto the expiation; wherefore when born He was called Christ; and thus it proceeds, who is called Christ.”