Note: As the Church has said, the manual has been prepared as the primary source of lesson material. These supplements, from general conference addresses, are meant only as a complement to your study on this lesson’s topic.
Supplement is from Elder Jeffrey R. Holland's talk, "Lord, I Believe" from the April 2013 general conference:
In the growth we all have to experience in mortality, the spiritual equivalent of this boy’s affliction or this parent’s desperation is going to come to all of us. When those moments come and issues surface, the resolution of which is not immediately forthcoming, hold fast to what you already know and stand strong until additional knowledge comes. It was of this very incident, this specific miracle, that Jesus said, “If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.”6 The size of your faith or the degree of your knowledge is not the issue—it is the integrity you demonstrate toward the faith you do have and the truth you already know.