Augustine of Hippo
Catena Aurea · Johannesevangelium 16
I have yet many things to say unto you, but ye cannot bear them now. Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself: but whatsoever he shall hear, that shall he speak; and he will shew you things to come. He shall glorify me: for he shall receive of mine, and shall shew it unto you. All things that the Father hath are mine: therefore said I, that he shall take of mine, and shall shew it unto you.
(Tr. xcix) Nor let the use of the future tense perplex you: that hearing is eternal, because the knowledge is eternal. To that which is eternal, without beginning, and without end, a verb of any tense may be applied. For though an unchangeable nature does not admit of was, and shall be, but only is, yet it is allowable to say of It, was, and is, and shall be; was, because It never began; shall be, because It never shall end; is, because It always is.