14 When one of those who were reclining at the table with Him heard this, he said to Him, "Blessed is everyone who will eat bread in the kingdom of God!" 16 But He said to him, "A man was giving a big dinner, and he invited many; 17 and at the dinner hour he sent his slave to say to those who had been invited, 'Come; for everything is ready now.' 18 "But they all alike began to make excuses. The first one said to him, 'I have bought a piece of land and I need to go out and look at it; please consider me excused.' 19 "Another one said, 'I have bought five yoke of oxen, and I am going to try them out; please consider me excused.' 20 "Another one said, 'I have married a wife, and for that reason I cannot come.' 21 "And the slave came back and reported this to his master. Then the head of the household became angry and said to his slave, 'Go out at once into the streets and lanes of the city and bring in here the poor and crippled and blind and lame.' 22 "And the slave said, 'Master, what you commanded has been done, and still there is room.' 23 "And the master said to the slave, 'Go out into the highways and along the hedges, and compel them to come in, so that my house may be filled. 24 'For I tell you, none of those men who were invited shall taste of my dinner.'" (Luke 14:15-24)In this story from Jesus, a man was getting married and invited many. They all had excuses. So he sent out his servants to the streets. Notice that he didn't tell his servants to "invite" them. "Go out at once into the streets and lanes of the city and bring in here the poor and crippled and blind and lame." Lest you think I'm jumping to conclusion, in the next phase when there was still room he commanded, "Compel them to come in." That is, the first call to all the "nice people" was an invitation. After that it was a command.
Jesus said, "Many are called ..." (Matt 22:14). Invitation. So our altar calls, our "Ask Jesus into your heart" calls, our "Accept Jesus as your personal savior" calls might work in the first phase, the invitation. But note the results of the invitation. No one came. Many excuses, but all asked to be excused. This was what broke Jesus's heart. "O Jerusalem, Jerusalem, the city that kills the prophets and stones those sent to her! How often I wanted to gather your children together, just as a hen gathers her brood under her wings, and you would not have it!" (Luke 13:34) An unaccepted invitation.
In fact, prior to Charles Finney (1792-1875) you didn't hear about altar calls. You didn't hear invitations. You heard warnings to repent. We know that when the 3,000 were saved at Pentecost, Peter said, "For the promise is for you and your children and for all who are far off, as many as the Lord our God will call to Himself." (Acts 2:39) At the end of Paul's sermon in Persidia Antioch we read, "When the Gentiles heard this, they began rejoicing and glorifying the word of the Lord; and as many as had been appointed to eternal life believed." (Acts 13:48) Lydia of Thyatira was saved when "the Lord opened her heart to respond to the things spoken by Paul." (Acts 16:14)
The term is not "Please", but "Come!" And notice, from the story, who is compelled to come: "the poor and crippled and blind and lame." The poor in spirit (Matt 5:3), the spiritually empty. Those at the end of their resources with no other way out. The spiritually crippled without the arrogance or ability to get around. Those who can't even see, blinded by the god of this world. Those who are barely limping along. The spiritually homeless in the highways and hedges. The healthy and wealthy aren't a part of this. No invitation. When Jesus called His disciples it was "Come, follow Me," not "if you want to."
By now, of course, you've likely forgotten my first answer to the question, "Invitation or command?" The answer was "Yes." Yes, invite. I'm not saying otherwise. But notice that the predominant position in Scripture is that it is God's work to bring them in. He appoints, opens hearts, and calls. Invitations are general and typically don't work. But those whom God has intended to reach are compelled to come. It's a command. It's a command you're invited to obey ... and, of course, there are consequences to either choice.