I was saved when I was 43 years old. At the time just before grace came and released me from spiritual bondage, I was working two jobs. In the morning I'd work from 6:30-10:30 putting up Post Office mail. Sorting the mail behind the wall of PO Boxes, I could hear the conversations occurring in the lobby. There was a particular Bible-believing pastor who used to come in and cheerfully greet everyone. It wasn't one or two seconds before he would mention Jesus. Not 'Lord', or "Him', or 'God', but he'd say "Jesus". Things like, "Isn't it a great day on Jesus' world?" or "How are you on this day Jesus made?"
I'd become inflamed when I heard the name of Jesus. I believed that there was a God, the existence of the world in its complexity made it obvious. I was one whom the verse in Romans 1:19-20 applies,
For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.
However, I was also one for which the previous verse applied, too,
For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth.
And, what truth was I suppressing? Jesus, for He IS the truth. Therefore any mention of Jesus by anyone, with all its attached concepts- sin, repentance, wrath, inflamed my heart and mind and I suppressed it all.
When I'd hear that name I'd push the mail into the PO Boxes a little harder, I'd grind my teeth, I'd mutter to myself, "Why doesn't he shut up? Doesn't he know nobody wants to hear that bunk? Doesn't he know that nobody's listening??"
Of course, lol, I was listening.
Soon after that, my carefully built fortresses I'd built in my heart and mind were as wafers and wisps in the face of Jesus' power who, in His irresistible grace, in His timing, instantly crumbled them all down. I became a believer.
The lessons there were some I never forgot. Please allow me to share these few tidbits.
I know we feel funny when we witness to people. Sometimes we think we have to approach people in a way to share deep, complicated, theological truths in a private setting. Sometimes we beat ourselves up for missing an opportunity, or failing to be clear, or for being fearful we'll forget critical component.
When we speak to each other as believers, or when we to those we interact with as we go through our daily life (clerks, tellers, cashiers, etc), we should say the name of Jesus, specifically. Saying His name in the public square has power. Not as in magic genie power, but because the name of Jesus is the only name, the name above all names, and the name upon which we come to salvation, the name of Jesus incites people.
Secondly, have conversations about Jesus in the public sphere. Speak of him in the college cafeteria, in the meeting before it begins, at the coffee counter. Just a quick exchange with the friend you're with of what you learned about a specific verse, or reciting a scripture, or an insight regarding a parallel verse. Others around you hear these conversations. You may never know who heard them, as the pastor never knew I was listening, but the Holy Scriptures have impact upon whom the Lord decides they will have impact. Speak His truths in public, the word will not come back empty.
Of course we do want to witness as to the full message when we can. But when we can't, don't feel like you've failed. Speak His name or a few verses to someone in the public square. The name of Jesus and His word has power to chip away at the hardest of hearts.