revelation about Revelation

I was just listening to Matthew Gallatin and he was talking about sola scriptura. He mentioned the use of Rev. 22:18-19 as support for sola scriptura and then read the passage. As he was reading, before he said anything more, the light bulb went off in my head and I practically gasped from surprise at the obvious:

Revelation 22:18-19
"For I testify unto every man that heareth the words of the prophesy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book. And if any man shall take away from the words of the book of this prophesy, God shall take away his part out of the book of life, and out of the holy city and from the things which are written in this book."

Advocates of sola scriptura heavily rely on this passage: to them "the book" mentioned is the complete, Old and New Testament Bible--the complete canon. However, the book in question is plainly "this prophesy" of St John and not the entire New Testament canon (which did not exist at the time). In fact, the book of Revelation almost didn't make it into the final New Testament canon.

Nowhere in Scripture does it say that ALL the important doctrines and traditions that Christians are to follow are spelled out in the letters written by the apostles to the churches (esp in those specific ones that made it into the complete canon). And nowhere does it say that any practice not specifically spelled out in the Scriptures is to be rejected (unless Rev 22;18-19 is misinterpreted).

One must presuppose sola scriptura to be true in order to interpret the passage to be referring to the complete canon of the Bible as we know it today.

the 17th Kathisma

I have been reading the 17th Kathisma of the Psalter for my departed Grandmother and am interested to learn the specific reasons why this particular Kathisma was chosen.

Personally, as I read it I think, "This is not describing me at all!" and that's partly why I wondered why it would be read for me at my departure from this life. Here is a quote that directly addresses my question:

"At this service the 17th Kathisma (17th Kathisma — a Kathisma is one of the 20 divisions of the Psalter. The 17th Kathisma is comprised solely of Psalm 118 (Psalm 119 in the King James Version), the longest psalm in the Psalter) is read, which reveals to us the condition of our heart, and like a magnet draws out of it everything passionate and sinful which prevents us from approaching the Lord." (The One Thing Needful)

As I, a sinner, read it, it really does seem to turn into a prayer of compunction followed with the hope that someday, somehow I will be able to pray Prophet David's words from a pure heart.

Please share if you have learned anything about it or find anything!