That we are not to obey our own will, but the will of God
In the Gospel according to John: “I came not down from heaven to do my own will, but the will of Him that sent me.” Of this same matter, according to Matthew: “Father, if it be possible, let this cup pass from me; nevertheless, not what I will, but what You will.” Also in the daily prayer: “Your will be done, as in heaven, so in earth.” Also according to Matthew: “Not every one who says unto me, Lord, Lord, shall enter into the kingdom of heaven; but he who does the will of my Father which is in heaven, he shall enter into the kingdom of heaven.” Also according to Luke: “But that servant which knows his Lord's will, and obeyed not His will, shall be beaten with many stripes.” In the Epistle of John: “But he that does the will of God abides for ever, even as He Himself also abides for ever.”
Source: The Treatises of Cyprian (New Advent)