To ensure the flock of the faithful is in regular marriages and not committing adultery/bigamy/fornication, and because it is a Sacrament (Ephesians 5.32).
Authority - Matthew 16.16-18, 18.17-18, 1 Cor. 7.12-15, etc.
I did not ask you is Peter is the rock, I asked where the authority to dissolve a marriage calling it "irregular" exists in scripture.
Where is the scriptural precedent to say that vows taken are not "regular"
Mark :10:9 Therefore what God has joined together, let man not separate."
Mat 19:9 And I say unto you, Whosoever shall put away his wife, except [it be] for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.
Hbr 13:4 Marriage [is] honourable in all, and the bed undefiled: but whoremongers and adulterers God will judge.
Nowhere does the bible say unless there are any vows that are "irregular" and can be declared so by the church..
It was not until the middle ages that the church claimed authority over marriage when it was an "economic unit" or one that secured treaties and kingdoms.
So then they assumed the ability to regulate it
So there is no biblical precedent for the church to make the determination that any marriage is invalid