One good method of testing your memorization of long Bible passages is to strip out most of the word in the verse and leave only the first letter.  It looks like this:

He is the i______c of the i________ ______, the f_______ of a________ ________. (Colossians 1:15)

If you’d like to practice in this way, you can find some passages prepared here:

• Colossians 1 memory test
• Colossians 3 memory test