The "Did you know?" section of  the email contained this:

One familiar example of metathesis is our word "thrill," which was "thyrlian" in  Old English and "thirlen" in Middle English. By the late 16th century, native  English speakers had switched the placement of the "r" to form "thrill." Another  example is the alteration of "curd" into "crud" (the earliest sense of which  was, unsurprisingly, "curd"). It probably won't surprise you to learn that the  origin of "metathesis" lies in the idea of transposition — the word was borrowed  into English in the mid-16th century and derives, via Late Latin, from the Greek  verb "metatithenai," meaning "to transpose."

"Transposition" is the most common definition and the most relevant to Scripture.

"What does swapping two letters in a word have to do with anything in the Bible?" you might ask.

Well let me tell you: it has nothing to do with anything in the Bible.  At least nothing to do with grammar and letters changing position.  Instead we find some ideas changing position in the book of Hebrews.

As Merriam-Webster noted above the English word metathesis comes from the Greek verb metatithenai.  We actually find the Greek word metatithenai in the Greek of Hebrews chapter 7.

Now if perfection was through the Levitical priesthood (for on the basis of it the people received the Law), what further need was there for another priest to arise according to the order of Melchizedek, and not be designated according to the order of Aaron? For when the priesthood is changed, of necessity there takes place a change of law also. (Hebrews 7:11-12)

The Hebrew word behind the NASB word "changed" is metatithemi from which we get our word of the day metathesis.  We know the word means to transpose and in this context it means to "change position".  Some teach that "the Law was done away with by Christ".  Christ actually taught the exact opposite and told his followers

Do not think that I came to abolish the Law or the Prophets; I did not come to abolish but to fulfill. (Matthew 5:17)

The passage in Hebrews 7 teaches us that it was not abolished but was transposed (metatithemi) or switched.  Switched with what, though?

The flawed and limited understanding of the Torah (with the Levitical priesthood as "rulers" over the people of Isra'el) was switched with the fullness of the Torah that Messiah provided (with the Melchizedek-ian priesthood of Messiah as "servant" of the people of Isra'el).  As Messiah said "If anyone wants to be first, he shall be last of all and servant of all." (Mark 9:35).  And indeed, Messiah was the greatest servant of all.

Now to the King eternal, immortal, invisible, the only God, be honor and glory forever and ever. Amen. (1 Tim 1:17)