It has been said that Both Jesus in the gospel and Paul in Acts primarily went and spoke in places where they were invited. While I grant that they went where they were invited to speak (who wouldn't). But why were they invited in? In Jesus case we often see He invited Himself places (as was of course His right). But what often instigated invites to synagogues and homes, etc. to this unknown itinerant Rabbi?
14 Now after John was arrested, Jesus came into Galilee, proclaiming the gospel of God, 15 and saying, “The time is fulfilled, and the kingdom of God is at hand; repent and believe in the gospel. - Mark 1:14-15
38 And he said to them, “Let us go on to the next towns, that I may preach there also, for that is why I came out.” - Mark 1:38
Jesus came to preach. He did it in synagogues, in homes, on hillsides, on boats, as He was walking to and fro. He came to preach and He preached. Everywhere!
So, what about Paul? How'd he get invites?
16 Now while Paul was waiting for them at Athens, his spirit was provoked within him as he saw that the city was full of idols. 17 So he reasoned in the synagogue with the Jews and the devout persons, and in the marketplace every day with those who happened to be there. 18 Some of the Epicurean and Stoic philosophers also conversed with him. And some said, “What does this babbler wish to say?” Others said, “He seems to be a preacher of foreign divinities”—because he was preaching Jesus and the resurrection. 19 And they took him and brought him to the Areopagus, saying, “May we know what this new teaching is that you are presenting? 20 For you bring some strange things to our ears. We wish to know therefore what these things mean.” - Acts 17:16-20
Ahh there it is. Like Jesus (good model to follow), Paul got provoked by the idolatry of the pagans around him and he started debating (Yes, the Greek makes clear as does scriptural context throughout the New Testament that "reasoning" included debating and preaching. But it actually plain says he did those things too.) and preaching daily in the marketplace. Until in exasperation and/or curiosity the philosophers "invite" (the text says "took" and "brought" but hey invite works) Paul to come speak formally.
These things still happen today. I can't tell you how many times my friends and I have been preaching in the open air and end up in long and deep one to one or small group conversations. Even among folks who start off angry by our message and/or method. More times than not, if they are willing to talk calmly, they'll leave shaking our hand and/or with us thanking each other for the conversation.
My friends, not everybody is a preacher. But every Christian has an obligation (a commission, a pretty great one really) to proclaim the good news of our salvation to fellow image bearers. Please don't be prejudicial against lost sinners who need the gospel by only taking time to reach those you have relational credit with. Go to the lost everywhere. In and out of your comfort zones and build immediate relationships on law and gospel truth. You may make a friend or confirm an enemy. But you will have established that relationship on the solid rock of Jesus Christ.
When we proclaim His law and Gospel truth, we have His aroma. To some it will be life and to others death. The message will be foolishness or the power of God. A stumbling block or the rock to build a life with a solid foundation on. Just cast and water the seed friends. God will make it grow or not. Be faithful to God and your eternal relationship to Christ in your temporary relationships here on earth. Whether they be lifetime ones or seconds long as you pass a gospel tract or call for someone to repent and believe, and every length relationship in between. Remain faithful and God will bring the fruit in His time for His glory and for the good of His people, forever. God bless you all saints! Soli Deo Gloria!