It is the first principle of the gospel to know for a certainty the character of God, ...and that 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; ...you have got to learn how to be Gods yourselves, and to be kings and priests to God, the same as all Gods have done before you, namely, by going from one small degree to another,... from exaltation to exaltation, until you attain to the resurrection of the dead, and are able to dwell in everlasting burnings. and to sit in glory, as do those who sit enthroned in everlasting power.
Teachings of the Prophet Joseph Smith, p. 346-347, History of the Church, Vol. 6, Ch. 14, p. 305-6
"The Father is a glorified, perfected, resurrected, exalted man who worked out his salvation by obedience to the same laws he has given to us so that we may do the same."
Bruce R. McConkie, A New Witness for the Articles of Faith, p. 64
"For as we have a Father in heaven, so also we have a Mother there, a glorified, exalted, ennobled Mother."
Apostle Melvin Ballard, as quoted in Achieving a Celestial Marriage, 1976, p. 129
“People tell us, ‘You don’t believe in one God; you believe in three Gods.’ And the answer is, ‘Yes, we do.’ If that is polytheism then we are.”
Truman Madsen, BYU professor (emeritus), 150-Year- Old Debate: Are Mormons `Really Christian’? San Francisco Chronicle, April 8, 1996