Of God, and of the Holy Trinity

Westminster Confession of Faith 
(1646)

Chapter II

I. There is but one only,[1] living, and true God,[2] who is infinite in being and perfection,[3] a most pure spirit,[4] invisible,[5] without body, parts,[6] or passions;[7] immutable,[8] immense,[9] eternal,[10] incomprehensible,[11] almighty,[12] most wise,[13] most holy,[14] most free,[15] most absolute;[16] working all things according to the counsel of His own immutable and most righteous will,[17] for His own glory;[18] most loving,[19]gracious, merciful, long-suffering, abundant in goodness and truth, forgiving iniquity, transgression, and sin;[20] the rewarder of them that diligently seek Him;[21] and withal, most just, and terrible in His judgments,[22]hating all sin,[23] and who will by no means clear the guilty.[24]

II. God has all life,[25] glory,[26] goodness,[27] blessedness,[28] in and of Himself; and is alone in and unto Himself all-sufficient, not standing in need of any creatures which He has made,[29] nor deriving any glory from them,[30] but only manifesting His own glory in, by, unto, and upon them. He is the alone fountain of all being, of whom, through whom, and to whom are all things;[31] and has most sovereign dominion over them, to do by them, for them, or upon them whatsoever Himself pleases.[32] In His sight all things are open and manifest,[33] His knowledge is infinite, infallible, and independent upon the creature,[34] so as nothing is to Him contingent, or uncertain.[35] He is most holy in all His counsels, in all His works, and in all His commands.[36] To Him is due from angels and men, and every other creature, whatsoever worship, service, or obedience He is pleased to require of them.[37]

III. In the unity of the Godhead there be three Persons of one substance, power, and eternity: God the Father, God the Son, and God the Holy Ghost.[38] The Father is of none, neither begotten nor proceeding; the Son is eternally begotten of the Father; [39] the Holy Ghost eternally proceeding from the Father and the Son. [40]

Source: http://www.reformed.org/documents/wcf_with_proofs/