Mac Geek Gab Stephan shared a neat tip with us. As it turns out, you can use the arrow keys in Mac Messages like you can in Terminal.
Previously Sent Texts
In the text field where you type your message, you can press Option + Up or Option + Down to browse through messages you’ve sent before. You can do the same in Terminal, although you don’t have to press Option.
It’s a cool feature you could use if you need to correct a message you just sent, and you can use keys instead of copying and pasting.