"Thus His saints, inspired by His holy will, desire many things which never happen. They pray,
e.g., for certain individuals—they pray in a pious and holy manner—but what they request He does
not perform, though He Himself by His own Holy Spirit has wrought in them this will to pray.
And consequently, when the saints, in conformity with God’s mind, will and pray that all men be
saved, we can use this mode of expression: God wills and does not perform,—meaning that He
who causes them to will these things Himself wills them. But if we speak of that will of His which
is eternal as His foreknowledge, certainly He has already done all things in heaven and on earth
that He has willed,—not only past and present things, but even things still future. But before the
arrival of that time in which He has willed the occurrence of what He foreknew and arranged before
all time, we say, It will happen when God wills. But if we are ignorant not only of the time in
which it is to be, but even whether it shall be at all, we say, It will happen if God wills,—not because
God will then have a new will which He had not before, but because that event, which from eternity
has been prepared in His unchangeable will, shall then come to pass." - City of God 22:2
