He's telling Lamoni that he was called by the spirit to teach. I love the wording in vs 35 where he says that that same spirit lives in each of us and that it gives knowledge and power.
34 Ammon said unto him: I am a man; and man in the beginning was created after the image of God, and I am called by his Holy Spirit to teach these things unto this people, that they may be brought to a knowledge of that which is just and true;
35 And a portion of that Spirit dwelleth in me, which giveth me knowledge, and also power according to my faith and desires which are in God.
We all have that spirit in us and we all have access to that same knowledge and power as long as our faith is in place. I need knowledge to come to my mind on many different issues each day and it's quite comforting to know that it's there and I just need to remember to draw on it. I often go looking for my answers elsewhere, but this was a great reminder to me that I have direct access to the spirit who will deliver the answers I need as long I remember to ask. The world so often filters into my life in a way that I think of searching online or in a book or within friend's experiences to find the things I'm looking for. For some reason I've had to learn this lesson more than once, but if I just remember to ask Heavenly Father first, he always delivers. He knows me and my particular situation better than any other "expert" and never fails to direct me to the things I am looking for.