Bede the Venerable — as excerpted in the Catena Aurea on Luke 11:1-4

“After the account of the sisters, who signified the two lives of the Church, our Lord is not without reason related to have both Himself prayed, and taught His disciples to pray, seeing that the prayer which He taught contains in itself the mystery of each life, and the perfection of the lives themselves is to be obtained not by our own strength, but by prayer. Hence it is said, And it came to pass, that, as he was praying in a certain place.”