Tertullian

For, because Jesus Christ was to introduce the second people (which is composed of us nations, lingering deserted in the world aforetime) into the land of promise, "flowing with milk and honey" (that is, into the possession of eternal life, than which nought is sweeter); and this had to come about, not through Moses (that is, not through the Law's discipline), but through Joshua (that is, through the new law's grace), after our circumcision with "a knife of rock" (that is, with Christ's precepts, for Christ is in many ways and figures predicted as a rock ); therefore the man who was being prepared to act as images of this sacrament was inaugurated under the figure of the Lord's name, even so as to be named Jesus.