WHICH IS, WHICH WAS, WHICH IS TO COME – (an appellation or Title of Jesus) equivalent to the tetragrammaton (YHWH), the Eternal One, I AM THAT I AM
“John to the seven churches which are in Asia: Grace be unto you, and peace, from him which is, and which was, and which is to come; and from the seven Spirits which are before his throne;” Rev 1:4