Saint-Cyprian-of-CarthageContinued from here

We ask that the will of God may be done both in heaven and in earth, each of which things pertains to the fulfilment of our safety and salvation.

For since we possess the body from the earth and the spirit from heaven, we ourselves are earth and heaven; and in both—that is, both in body and spirit—we pray that God’s will may be done.

For between the flesh and spirit there is a struggle; and there is a daily strife as they disagree one with the other, so that we cannot do those very things that we would, in that the spirit seeks heavenly and divine things, while the flesh lusts after earthly and temporal things.

Therefore we ask that, by the help and assistance of God, agreement may be made between these two natures, so that while the will of God is done both in the spirit and in the flesh, the soul which is new-born by Him may be preserved.

[…] And therefore we make it our prayer in daily, yea, in continual supplications, that the will of God concerning us should be done both in heaven and in earth.

Because this is the will of God, that earthly things should give place to heavenly, and that spiritual and divine things should prevail.

[…] The Lord commands and admonishes us even to love our enemies, and to pray even for those who persecute us.

Accordingly, we should ask for those who are still earth, and have not yet begun to be heavenly, that even in respect of these God’s will should be done, which Christ accomplished in preserving and renewing humanity.

The disciples are now called by Him not earth, but the salt of the earth, and the apostle designates the first man as being from the dust of the earth, but the second from heaven.

So it is reasonable that we, who ought to be like God our Father, who makes His sun to rise upon the good and bad and sends rain upon the just and the unjust, should so pray and ask by the admonition of Christ as to make our prayer for the salvation of all men:

that “as in heaven”—that is, in us by our faith—the will of God has been done so that we might be of heaven; so also “in earth”—that is, in those who believe not—God’s will may be done, that they who as yet are by their first birth of earth, may, being born of water and of the Spirit, begin to be of heaven.

Cyprian of Carthage (d.258): On The Lord’s Prayer, 16-17.