2 Thessalonians 3:17
This greeting is in my own hand — Paul. This is my mark in every letter; it is the way I write.
What it says
He notes that this greeting is in his own hand, Paul's, which is the distinguishing mark in every letter.
What it is doing
It confirms the letter's authenticity.
In context
16Now may the Lord of peace Himself give you peace at all times and in every way. The Lord be with all of you. 17This greeting is in my own hand — Paul. This is my mark in every letter; it is the way I write. 18The grace of our Lord Jesus Christ be with all of you.