Revelation 22:6

We have here a solemn ratification of the contents of this book, and particularly of this last vision (though some think it may not only refer to the whole book, but to the whole New Testament, yea, to the whole Bible, completing and confirming the canon of scripture); and here, 1. This is confirmed by the name and nature of that God who gave out these discoveries: he is the Lord God, faithful and true, and so are all his sayings. 2. By the messengers he chose, to reveal these things to the world; the holy angels showed them to holy men of God; and God would not employ his saints and angels in deceiving the world. 3. They will soon be confirmed by their accomplishment: they are things that must shortly be done; Christ will make haste, he will come quickly, and put all things out of doubt; and then those will prove the wise and happy men who have believed and kept his words. 4. By the integrity of that angel who had been the apostle's guide and interpreter in these visions; this integrity was such that he not only refused to accept religious adoration from John, but once and again reproved him for it.

— Matthew Henry's Concise Commentary (public domain)

These sayings are true--thrice repeated (Rev 19:9; Rev 21:5). For we are slow to believe that God is as good as He is. The news seems to us, habituated as we are to the misery of this fallen world, too good to be true [NANGLE]. They are no dreams of a visionary, but the realities of God's sure word. holy--so ANDREAS. But A, B, Vulgate, Syriac, and Coptic read, "(the Lord God of the) spirits (of the prophets)." The Lord God who with His Spirit inspired their spirits so as to be able to prophesy. There is but one Spirit, but individual prophets, according to the measure given them (Co1 12:4-11), had their own spirits [BENGEL] (Pe1 1:11; Pe2 1:21). be done--Greek, "come to pass."

— Jamieson-Fausset-Brown Commentary (public domain)