Passing arguments to a command in Bash script with spaces

I'm trying to pass 2 arguments to a command and each argument contains spaces, I've tried escaping the spaces in the args, I've tried wrapping in single quotes, I've tried escaping \" but nothing will work.

Here's a simple example.

#!/bin/bash -xv

ARG="/tmp/a b/1.txt"
ARG2="/tmp/a b/2.txt"

ARG_BOTH="\"$ARG\" \"$ARG2\""
cat $ARG_BOTH

I'm getting the following when it runs:

ARG_BOTH="$ARG $ARG2"
+ ARG_BOTH='/tmp/a\ b/1.txt /tmp/a\ b/2.txt'
cat $ARG_BOTH
+ cat '/tmp/a\' b/1.txt '/tmp/a\' b/2.txt
cat: /tmp/a\: No such file or directory
cat: b/1.txt: No such file or directory
cat: /tmp/a\: No such file or directory
cat: b/2.txt: No such file or directory