Paul's own hand - Part 2

2 Thessalonians 3:17 - I, Paul, write this greeting in my own hand, which is the distinguishing mark in all my letters. This is how I write.

Here is the explanation to why Paul wrote as he did at the end of Galatians (and elsewhere). It was simply his signature.

I wonder how many letters he wrote that have not been passed down to us. We can be certain that every letter that we need, we have. God has seen to that.