I will go back to the beginning before the world was, to show what kind of being God is. What sort of a being was God in the beginning? Open your ears and hear, all ye ends of the earth...God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens! That is the great secret...He was once a man like us; yea, that God himself, the Father of us all, dwelt on an earth, the same as Jesus Christ himself did (Teachings of the Prophet Joseph Smith, pp. 435-436).This conflicts, according to our critics, with the statements of scripture that God is "from everlasting to everlasting." I suppose it does conflict if you interpret "everlasting" to mean "forever and ever," but is that how it should be interpreted?
The Hebrew word olawm (Strongs 5769), literally means a time "concealed" or "out of mind." It can only be interpreted as "forever" in the future or the past figuratively. In other words, these passage literally speak of God as being God from a time "out of mind" from some point that is "concealed" from us.
President Joseph Fielding Smith commented:
"From eternity to eternity" means from the spirit existence through the probation which we are in, and then back again to the eternal existence which will follow...We all existed in the first eternity. I think I say can of myself and others, we are from eternity; and we will be to eternity everlasting, if we receive the exaltation. The intelligent part of man was never created but always existed. That is true of each of us as well as it is of God, yet we are born sons and daughters of God in the spirit and are destined to exist forever. Those who become like God will also be from eternity to eternity (Doctrines of Salvation, 1:12).In other words, God is from everlasting to everlasting because he, like us, came from a spirit existence (one eternity) and then passed through a mortal probation into exaltation (the other eternity). Likewise, all mankind is from eternity, and those of us who are exalted will be to eternity. Eternity the place where spirit offspring is brought forth. We all came from one eternity. The exalted will in the hereafter bring forth their own spirit offspring. Therefore, they will be from eternity to eternity. This is in harmony with D&C 132:19-20.
And again, verily I say unto you, if a man marry a wife by my word, which is my law, and by the new and everlasting covenant, and it is sealed unto them by the Holy Spirit of promise, by him who is anointed, unto whom I have appointed this power and the keys of this priesthood; and it shall be said unto them—Ye shall come forth in the first resurrection; and if it be after the first resurrection, in the next resurrection; and shall inherit thrones, kingdoms, principalities, and powers, dominions, all heights and depths—then shall it be written in the Lamb’s Book of Life, that he shall commit no murder whereby to shed innocent blood, and if ye abide in my covenant, and commit no murder whereby to shed innocent blood, it shall be done unto them in all things whatsoever my servant hath put upon them, in time, and through all eternity; and shall be of full force when they are out of the world; and they shall pass by the angels, and the gods, which are set there, to their exaltation and glory in all things, as hath been sealed upon their heads, which glory shall be a fulness and a continuation of the seeds forever and ever.Then shall they be gods, because they have no end; therefore shall they be from everlasting to everlasting, because they [the seeds?] continue; then shall they be above all, because all things are subject unto them. Then shall they be gods, because they have all power, and the angels are subject unto them.
I bring this all up simply to show that this criticism, like many others, leveled against the doctrines of the LDS Church is based on the preconceived notions of "mainstream" Christianity. While most in "mainstream" Christianity would interpret "from eternity to eternity" as "for ever and ever," LDS interpret it to mean "from one eternity (the creation of spirit children) to the next eternity (the creation of spirit children)." So, LDS can insist on one hand that God was once a mortal man and on the other hand fully accept and agree with the scriptures that say he is "from eternity to eternity." For us, "from eternity to eternity" means exactly that: God was once a man like you or I. Further, we mortals can become "from everlasting to everlasting" and become gods ourselves just as God the Father has done.