From The Encyclopedia of Mormonism
Author: Thomasson, Gordon C.
Circumcision (Gen. 17:9-14) was the sign of the covenant Abram made with God (Gen. 17:10), in token of which his name was changed to Abraham (Gen. 17:5; cf. Luke 1:59,2:21). Joseph Smith's translation of the Bible indicates that the performance of circumcision on the eighth day after birth symbolized "that children are not accountable before me until they are eight years old" (JST Gen. 17:4-20; cf. D&C 68:25;74:1-7). The rite is attested in the intertestamental period (1 Macc. 1:15, 60-61; 2 Macc. 6:10) and is still observed in Judaism and Islam. Circumcision as a necessity for salvation became a major controversy in early Christianity (Acts 10:45;11:2;15:1-31), since it had become associated with the Law of Moses.
The Book of Mormon seems to imply the continuing practice of circumcision among its peoples from about 600 B.C. They "were strict in observing the ordinances of God, according to the Law of Moses" (e.g., Alma 30:3), apparently including the practice of circumcision. Near the end of Nephite history the Lord revealed to the prophet Mormon that "the law of circumcision is done away in me" (Moro. 8:8).
In modern times, Joseph Smith affirmed the perpetuity of the Abrahamic Covenant and defended the integrity of Judaism. Today, however, if Latter-day Saint males are circumcised, it is for cleanliness and health, not religious, reasons. From the beginning of the modern Church, the emphasis has been on circumcision of heart (cf. Deut. 10:16;30:6; Jer. 4:4; Ezek. 44:9). Such a heart is taken as a sign or token of one's covenants with Christ. This may be the understanding of "broken heart and contrite spirit" among Book of Mormon prophets (2 Ne. 2:7; 3 Ne. 12:19; Moro. 6:2) and in modern revelation (e.g., D&C 59:8). GORDON C. THOMASSON