In his encyclical Mediator Dei, Pius XII links liturgy with the last will of Jesus Christ.
||"But it is His will, that the worship He instituted and practiced during His life on earth shall continue ever afterwards without intermission. For he has not left mankind an orphan. He still offers us the support of His powerful, unfailing intercession, acting as our "advocate with the Father." He aids us likewise through His Church, where He is present indefectibly as the ages run their course: through the Church which He constituted "the pillar of truth" and dispenser of grace, and which by His sacrifice on the cross, He founded, consecrated and confirmed forever."|