Mosiah 18:6 - 18:10

Mosiah 18:6 And it came to pass that as many as believed him went thither to hear his words.

It was in this place that people went to listen to Alma preach.

Mosiah 18:7 And it came to pass after many days there were a goodly number gathered together at the place of Mormon, to hear the words of Alma. Yea, all were gathered together that believed on his word, to hear him. And he did teach them, and did preach unto them repentance, and redemption, and faith on the Lord.

Alma’s converts continued to increase in numbers. As they gathered together in Mormon, they listened to Alma preach the necessity for repentance and the atonement of the Lord brought about by faith in Him.

Mosiah 18:8 And it came to pass that he said unto them: Behold, here are the waters of Mormon (for thus were they called) and now, as ye are desirous to come into the fold of God, and to be called his people, and are willing to bear one another’s burdens, that they may be light;

Now Alma asks the people what they are willing to do to show their faithfulness in his teachings. Are they now willing to show that by being baptized. Are they willing to work with each other in helping each other to become better people in this life and help each other when in need.
[Being baptized means more than showing you conversion by being immersed in water. It means that you are willing to be a help and comfort to your fellowman. There is a responsibility that goes with this ordinance. You are saying that you will do more than just believe. You will do something for the welfare of others.]

Mosiah 18:9 Yea, and are willing to mourn with those that mourn; yea, and comfort those that stand in need of comfort, and to stand as witnesses of God at all times and in all things, and in all places that ye may be in, even until death, that ye may be redeemed of God, and be numbered with those of the first resurrection, that ye may have eternal life—

Alma asks them if they are willing to go so far as help those who morn because of various reasons; comfort those who feel down because of various burdens that they carry; and be an example of how a Christian should behave. Because if they were willing to do these simple things, they would indeed be saved in the kingdom of heaven and be part of the first resurrection.

Mosiah 18:10 Now I say unto you, if this be the desire of your hearts, what have you against being baptized in the name of the Lord, as a witness before him that ye have entered into a covenant with him, that ye will serve him and keep his commandments, that he may pour out his Spirit more abundantly upon you?

If the people want to join in such a cooperative association then what objection should they have to show that desire by being baptized. This symbolic gesture is to show that they are indeed willing to enter into such a covenant. That they will do as the Lord’s asks of them and they will be rewarded with the Spirit of the Lord.