After that first tremendous day was over, I imagine that the Twelve went home, attended to their families, and then met together again. They may have conferred together all that night and recorded the words which Jesus had spoken, so that they could deliver them again the next day. They would have learned the difficulty of being a servant, that it takes work through the lonely midnight hours to be able to render that kind of service to the people which the Lord wanted them to do.
What is unmistakable in 3 Nephi is that the Savior calls on everyone. It does not matter who they are, he wants them to “repent and come unto me” and to be one with him. The disciples are told to go out and bring as many as they can the next day. I imagine there were plenty who said, “I cannot come, I am not worthy,” or maybe “I am too skeptical.” But the crowd that assembled the second day was even larger than that on the first day, and those were people who responded to the call. They came when someone invited them and said, “Please come; you will not be disappointed.”
The Twelve were directing this; probably sending people out in various directions, “You go here, you go there.” We can suppose that anybody who was close by the temple could not have missed what was going on, so when it says “abroad,” it was probably referring people out in the outlying areas, maybe in the farmlands, who would not have been aware of what was going on. They wanted to bring in as many as possible.