He was clearly saying that their lives would be seen, that their words and deeds would be witnessed. Therefore, he warned them to "consider carefully how they listened." Curious, no? You will be seen so be careful how you listen instead of what you do or say? What could this mean?
For one thing, he is affirming that we will be receiving conflicting messages, some messages will resonate with the truth our our place as lamps and some messages denying that truth. Along with the Lord's encouragement that we are made to shine as lights in the world, the enemy comes along saying that we are dim bulbs that no one pays attention to, that our light is not going to make a difference - what we do won't really matter. Have you heard that voice?
The voices will continue, either affirming or denying our purpose and our worth. The Voice of Truth will affirm our role as a light in darkness, while the voice of the enemy will deny that and insist that our life is our own, that we can do and say what we want. "It's my life, I can do what I want. I'm not hurting anyone else." Really? No one depends on you for direction or support or encouragement?
The Voice of Truth tells us that we live legacies, that everything we do or say registers somewhere, with someone. The Lord warns us to be careful how we listen. Do not listen to the false voices that suggest our life is something of individual concern, no one will be observing, no one will depend on the light you were meant to provide. Those voices lie! Be careful how you listen. Lean in and listen to the Voice of Truth, understand how important your example is. Jus' Say'n.