1 Cor. 15:28 - "That God may be all in all"

Q.

Dave asks:

I still struggle with this verse and it's meaning, I see it used by Cults and ism's to support various beliefs.

"And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all." 1 Cor. 15:28

Is it saying "God may be all in all" as in we will see the Trinity reigning? (hope that makes sense) or that God will have put down all rebellion, as a result God is in all (everyone). I lean towards the first because of the context. Maybe I've missed the mark altogether? Supporting scripture sure would be nice.

A.
This verse appears to be the culmination and end of:

"yet for us there is but one God, the Father, from whom are all things and we exist for Him; and one Lord, Jesus Christ, by whom are all things, and we exist through Him. 1 Cor. 8:6"

And if we want further biblical elaboration, we can turn to Rev. chapters 21-22 and glean whatever we can glean.

I'll add one more related passage:

"I pray that the eyes of your heart may be enlightened, so that you will know what is the hope of His calling, what are the riches of the glory of His inheritance in the saints, and what is the surpassing greatness of His power toward us who believe. These are in accordance with the working of the strength of His might which He brought about in Christ, when He raised Him from the dead and seated Him at His right hand in the heavenly places, far above all rule and authority and power and dominion, and every name that is named, not only in this age but also in the one to come. And He put all things in subjection under His feet, and gave Him as head over all things to the church,which is His body, the fullness of Him who fills all in all." Eph 1:18-23

Steve