The temple holds the same place of importance to a Mormon as the cross does for Christians. They see it as the gateway to eternal life. Their emphasis on the temple is seen in the fact that many Mormons have a picture of a LDS temple hanging in a prominent place in their homes.
They believe the temple is the gateway to eternal life because in it, and only in it, are the ordinances necessary for exaltation carried out. "The principal purpose of temples is to provide the ordinances necessary for our exaltation in the celestial kingdom" (True to the Faith, p. 170). The specific ordinances which accomplish this are the endowment ceremony and eternal marriage.
Although those ordinances are very important, the most common activity performed in the temple are the ordinances for the dead: baptisms, endowments, and sealings. This activity, also known as temple work, helps Mormons progress toward exaltation.
Mormons refer to the temple as a place of worship, but only in the sense of carrying out these important sacred duties. No worship services, as Christians think of worship services, are held in the temple.
Not every Mormon is eligible to enter the temple. Their local leaders interview them to determine their worthiness. "You will be asked to confirm that you are morally clean and that you keep the Word of Wisdom, pay a full tithe, live in harmony with the teachings of the Church, and do not maintain any affiliation or sympathy with apostate groups" (True to the Faith, p. 172). If found worthy, they are given a temple recommend. This card, which is renewed every two years, gives them access to the temple.
Inside the temple, they must wear white temple clothing. "Dressed in white, you can feel a oneness and a sense of equality with others in the temple, for everyone around you is similarly dressed" (True to the Faith, p. 173). They also wear sacred undergarments at all times to remind them of the covenants they made in the temple. They believe these garments also provide protection against temptation and evil.
Biblical Christianity teaches that the temple was a central component of the Old Testament. It, however, bore no resemblance to LDS temples. Its purpose was to vividly show the people how their sins had separated them from God. It emphasized this by not allowing anybody but the priests to enter it. Even more striking was the fact that only the high priest, and he only one day a year, could enter the Holy of Holies. The ark of the covenant, which symbolized God’s presence, was found here.
The other striking element of the Old Testament temple was the sacrifice of animals. Day in and day out animals were sacrificed to illustrate that only through sacrifice could sin be atoned for. These sacrifices all pointed to Jesus.
When Jesus died, the veil of the temple was torn in two (Matthew 27:51). In this dramatic way, God indicated that Jesus, through his sacrifice, had removed our separation from God. Now there is no need for physical temples. Instead the Bible tells us the wonderful news that believers themselves are now God’s temple (1 Corinthians 1:16).