Christianity has claimed that part of being saved is to have the Lord himself to dwell in your heart. Joseph Smith clearly taught that this doctrine is false, the idea that the Father and the Son dwell in a man's heart is an old sectarian notion, and is false (DC 130:3). Therefore, we may not be able to have the Lord dwell in our hearts, but we certainly can receive his image in our countenances. This phrase may mean many things to many people but here are a few ideas. To receive his image in our countenance is a) to radiate the same kind of light and truth that his being radiates, b) to be such an example to others that they see the righteousness of God in our visage, c) to have all darkness turned to light by having an eye single to his glory, d) to look like the Lord, not in facial appearances, but in attitude and actions, e) to worthily represent the Lord, having taken upon ourselves his holy name at baptism.
"One measure of the new birth is the appearance of the new man. Paul described the process of salvation as obtaining 'the mind of Christ' (1 Corinthians 2:16); that is, learning to think as Christ thinks, believe as he believes, feel as he feels, and do as he would do. Peter described the same thing as partaking of 'the divine nature' (2 Peter 1:4), meaning that we must acquire the attributes of godliness. Joseph Smith explained: 'The Savior most clearly show[ed] unto us the nature of salvation, and what he proposed unto the human family when he proposed to save them- that he proposed to make them like unto himself, and he was like the Father, the great prototype of all saved beings; and for any portion of the human family to be assimilated into their likeness is to be saved; and to be unlike them is to be destroyed; and on this hinge turns the door of salvation' (Lectures on Faith 7:16). As a child learns by imitating and emulating parents and those older than himself, so we learn godliness by imitating others who have set an example in righteousness, especially Jesus Christ. Alma appropriately describes this process of becoming Christlike as receiving the image of Christ in our countenances." (McConkie and Millet, Doctrinal Commentary on the Book of Mormon, vol. 3, p. 30)