1] Consider first of all the Great Commission- given at least 5 times in the New Testament [Mt. 28:16-20, Mark 16:14-15, Luke 24:46-49, John 20:1923, Acts 1:8] "Go...teach," "Go...preach the Gospel," "Repentance and remission of sins should be preached...," "As my Father hath sent me, even so send I you," and "Ye shall be witnesses unto me."
Not once did Jesus mention a meal in connection with this. Not that it is wrong to have a meal with fellow Christians and even invite the lost. But it is NOT the New Testament plan of witnessing as was implied.
The words "Go, teach, preach the Gospel, preached, sent, send, be witnesses" certainly don't imply meals of fellowship with other Christians as the means to spread the Gospel.
Obviously inviting lost people to a meal and then deliberately presenting the Saviour is another way to win people to Christ [Levi did it] but it is not THE way given in the Great Commission. More on this later.
2] The thousands saved in the New Testament were not after people saw Christians having meals together but were after the Gospel was preached to crowds [Acts 2:14-41], after more preaching and the miracle-working power of God was manifested [Acts 5:12-14] and after public and house-to-house teaching/preaching [not meals] ceased not [Acts 5:42].
3] To be honest, sometimes meals are mentioned but they are incidental, not instrumental, to the salvation of souls. For instance in Acts 2:46 the meal is mentioned after the important fact of the believers "continuing daily with one accord in the temple". The emphasis of the believers unity has been emphasized throughout the chapter [v. 1, 42, the end of 46, and then again in 47. The meal, while good, was incidental.
4] We are not trying to minimize the importance of believers having fellowship around meals but that is not the emphasis of evangelism in the New Testament. In fact, Jesus said in Luke 14:12-14, "When thou makest a dinner or a supper, call not thy friends, nor thy brethren, neither thy kinsmen, nor thy rich neighbours; lest they also bid thee again, and a recompense be made thee. But when thou makest a feast, call the poor, the maimed, the lame, the blind: And thou shalt be blessed; for they cannot recompense thee: for thou shalt be recompensed at the resurrection of the just."
5] What did Paul do when he established the church in Ephesus? Did he have meals house-to-house or go house-to-house with the Gospel? What about it Paul? "Ye know, from the first day that I came into Asia, after what manner I have been with you at all seasons, Serving the Lord with all humility of mind, and with many tears, and temptations, which befell me by the lying in wait of the Jews: And how I kept back nothing that was profitable unto you, but have shewed you, and have taught you publicly, and from house to house, Testifying both to the Jews, and also to the Greeks, repentance toward God, and faith toward our Lord Jesus Christ." [Acts 20:18-21]
6] There is nothing wrong with having meals but let us not make it more important than giving the Gospel clearly to the lost and going to the lost with that purpose. Often I have heard of people saying "I just live my life so they see a difference." But the cults do the same thing. Many a cultist lives better than his fellow man. We must live the Christian life but that is to back up the words we speak- not to induce the lost to want to eat with us.
7] The man ended his words by saying "Maybe if we as Christians love each other more that would be enough of a testimony to work on someone's heart." "Maybe... that would be enough"? No, we have seen -the Gospel must be given. The lips are to be backed up by the life, the words backed up by the works- but the words are MORE important. No one ever got saved by following Christ's example- they were saved by trusting in Him. The leader of one cult advocated the view that Christ was a "way shower" - showing us the way. The Lord declared "I AM the Way!" [Jn. 14:6].
"And many of the brethren in the Lord, waxing confident by my bonds, are much more bold to speak the word without fear. Some indeed preach Christ even of envy and strife; and some also of good will: The one preach Christ of contention, not sincerely, supposing to add affliction to my bonds: But the other of love, knowing that I am set for the defence of the gospel. What then? notwithstanding, every way, whether in pretence, or in truth, Christ is preached; and I therein do rejoice, yea, and will rejoice. Phil. 1:14-18