So the answer I am getting here is that "Mormons build temples because Joe Smith said so."
There is a great deal in the New Testament which if one knows what they're looking for which we believe shows they did have temples. But, one could say Joseph just borrowed it from the Bible. As an example;
*John 20:30 And many other signs truly did Jesus in the presence of his disciples, which are not written in this book
The word signs is sēmeion in the greek and means; a sign, mark, token. When a Mormon hears that they sit up and take notice.
*Matt 16: 19 And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
Matt 17:3 And, behold, there appeared unto them Moses and Elias/Elijah talking with him.
This happened to Joseph when he was given the keys of the gathering, Peter had them too.
*1 Cor 15: 29 Else what shall they do which are baptized for the dead, if the dead rise not at all? why are they then baptized for the dead?
That is one of the purposes of having the keys of the kingdom,
*Eph 1& 3
9 Having made known unto us the mystery of his will, according to his good pleasure which he hath purposed in himself:
10 That in the dispensation of the fulness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in him:
14 For this cause I bow my knees unto the Father of our Lord Jesus Christ,
15 Of whom the whole family in heaven and earth is named,
This gathering of the family of God into one, another purpose of those keys.
*Eph 1:3 Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ:
*Heb 10
19 Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus,
20 By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh;
21 And having an high priest over the house of God;
22 Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water.
23 Let us hold fast the profession of our faith without wavering; (for he is faithful that promised
The house of God is the temple Jesus is our high priest, we are consecrated through the veil.
There's more but I think you can see my point, you will understand these passages differently than we will