2 Ne. 2:24; Moro. 7:22; Psalm 147:5; D&C 38:1-2; 88:41; Alma 13:7; 26:35; Isa. 66:18; History of the Church, Smith 4:597; 6:30; Lectures on Faith, p. 43; Doctrines of Salvation, Smith, 1:5-10
“Without the knowledge of all things God would not be able to save any portion of his creatures; for it is by reason of the knowledge which he has of all things, from the beginning to the end, that enables him to give that understanding to his creatures by which they are made partakers of eternal life; and if it were not for the idea existing in the minds of men that God had all knowledge it would be impossible for them to exercise faith in him.” (Joseph Smith, Lectures on Faith, 4:11)
“The notion that our God is still progressing in knowledge—that he is gaining new truths—seems to have come from … a misunderstanding of what is meant by eternal progression. God progresses in the sense that his kingdoms expand and his dominions multiply (see D&C 132:31; 63; Moses 1:39).” (R. Millet & J. F. McConkie, Doctrinal Commentary on the Book of Mormon, 1:247)
“God is Omniscient—By Him matter has been organized and energy directed. He is therefore the Creator of all things that are created; and ‘Known unto God are all his works from the beginning of the world.’ His power and His wisdom are alike incomprehensible to man, for they are infinite. Being Himself eternal and perfect, His knowledge cannot be otherwise than infinite. To comprehend Himself, an infinite Being, He must possess an infinite mind. Through the agency of angels and ministering servants He is in continuous communication with all parts of creation, and may personally visit as He may determine.” (James E. Talmage, Articles of Faith, pp. 43-44)