I used to share this verse with the teenage girls I worked with at our old church all the time. And I mainly used in this way:
"Stay away from those pesky boys. Guard your hearts, ladies!"
Tonight one of my best friends spoke this truth over me, that this verse doesn't just encapsulate romantic relationships. It's a caution, full of God-given wisdom, to apply to any situation where our heart can get all tangled up. She encouraged me to continue to guard my heart in a situation that was previously extremely hurtful. She confirmed what the Lord was speaking to me, that we do need to guard our hearts, because when we don't the effects spill over into everything in our lives.
So on that note...
I memorized this verse during my last year of college, but I figured tonight it was worthy of a card. And I obviously need to revisit this one, considering I argued with biblegateway.com that OH YES, PSALM 4:23 DOES SO EXIST. Or so I thought. :)
Check back tomorrow for a new card! Anything you're trying to memorize that you want made into a card?