The Father and Jesus have, from the beginning, planned to increase Their kind. The God kind is a family! It is headed by the Father and now consists of the Father and the Son, Jesus Christ.
These two have always existed and always will exist. Their plan and desire are to add to Their kind—"bringing many sons to glory" (Hebrews 2:10 Hebrews 2:10For it became him, for whom are all things, and by whom are all things, in bringing many sons to glory, to make the captain of their salvation perfect through sufferings.
American King James Version×). Just as all life was made to reproduce after its own kind as stated throughout Genesis 1, so God patterned man after the God kind. This is the ultimate meaning of Gensis 1:26, where God says, "Let Us make man in Our image, according to Our likeness."
This is a two-stage process. First, God made man physical, of the dust of the earth. Then, through conversion and faith in Christ and obedience to God's spiritual law of love, men and women become a new spiritual "creation" (2 Corinthians 5:17 2 Corinthians 5:17Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
American King James Version×; Ephesians 4:24 Ephesians 4:24And that you put on the new man, which after God is created in righteousness and true holiness.
American King James Version×). This leads to the final birth of new children into the divine family, who are then "like" Christ, Himself the firstborn Son of God (Romans 8:29 Romans 8:29For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brothers.
American King James Version×; Galatians 4:19 Galatians 4:19My little children, of whom I travail in birth again until Christ be formed in you,
American King James Version×; 1 John 3:2 1 John 3:2Beloved, now are we the sons of God, and it does not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is.
American King James Version×).
Indeed, just as human children are the same kind of beings as their parents (that is, human beings), so will God's children be the same kind of beings as the Father and Christ (that is, divine beings). This is the awesome destiny of mankind! The God family will expand through God's wonderful plan as revealed in His Word.
All children of this family will forever in the future willingly be under the ultimate sovereignty, authority and leadership of the Father first and then the Son (see 1 Corinthians 15:24-28 1 Corinthians 15:24-28  Then comes the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
 For he must reign, till he has put all enemies under his feet.
 The last enemy that shall be destroyed is death.
 For he has put all things under his feet. But when he said all things are put under him, it is manifest that he is excepted, which did put all things under him.
 And when all things shall be subdued to him, then shall the Son also himself be subject to him that put all things under him, that God may be all in all.
American King James Version×). Led by the Father and Christ, the members of this divine family will share a glorious and righteous eternity into the future.
This, then, is the sense in which God is a family—indeed a growing family, presently comprised of two divine Beings, the Father and Christ the firstborn, yet ultimately to be joined by a vast multitude of others. (To learn more, request or download our free booklet Who Is God?)