During the reformation, where people came back to the Bible, Martin Luther comments on the subject of prayer. Prayer had to be big in that day because of all the strong religion pulling people away from the Bible. I am sure Luther prayed much.
But the principle went still further; for it vindicated for the laity the possession of spiritual faculties and powers the same in kind as those of the clergy. All Christian men are admitted to the privilege of priesthood, and are “worthy to appear before God to pray for others, and to teach one another mutually the things which are of God. — from First Principles of the Reformation (95 Theses)
So too His priesthood does not consist in the outward display of vestments and gestures, as did the human priesthood of Aaron and our ecclesiastical priesthood at this day, but in spiritual things, wherein, in His invisible office, He intercedes for us with God in heaven, and there offers Himself, and performs all the duties of a priest; as Paul describes Him to the Hebrews under the figure of Melchizedek. Nor does He only pray and intercede for us; He also teaches us inwardly in the spirit with the living teachings of His Spirit. Now these are the two special offices of a priest, as is figured to us in the case of fleshly priests, by visible prayers and sermons.
— from: First Principles of the Reformation (95 Theses)