Infant Baptism

Moroni 8:10–12
10 Behold I say unto you that this thing shall ye teach—repentance and baptism unto those who are accountable and capable of committing sin; yea, teach parents that they must repent and be baptized, and humble themselves as their little children, and they shall all be saved with their little children.
11 And their little children need no repentance, neither baptism. Behold, baptism is unto repentance to the fulfilling the commandments unto the remission of sins.
12 But little children are alive in Christ, even from the foundation of the world; if not so, God is a partial God, and also a changeable God, and a respecter to persons; for how many little children have died without baptism!

Teachings of Presidents of the Church: Joseph Smith (2007), 176
“The Lord takes many away, even in infancy, that they may escape the envy of man, and the sorrows and evils of this present world; they were too pure, too lovely, to live on earth; therefore, if rightly considered, instead of mourning we have reason to rejoice as they are delivered from evil, and we shall soon have them again.”