I can only assume that they thought of the concept in a contemporary way that the scriptures described it. Like this:
Rom 8:14-18 : 14 For as many as are led by the Spirit of God, they are the sons of God. 15 For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption, whereby we cry, Abba, Father. 16 The Spirit itself beareth witness with our spirit, that we are the children of God: 17 And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together. 18 For I reckon that the sufferings of this present time are not worthy to be compared with the glory which shall be revealed in us. KJV
There is nothing here about humans being able to rescind or opt out. That is a man-made invention which makes the Spirit's witness a LIE, BTW. Do you suppose that if the Spirit testifies of a man one day, that He should be ready to amend His testimony based on the free will of that man to throw away his adoption, and/or then regain it again the next day? Does that really sound reasonable to you? Does that really sound like what this scripture is saying to you?
Amen, FK. What a straightforward verse of God's merciful decree. The Holy Spirit is self-authenticating.
"Know ye not that ye are the temple of God, and that the spirit of God dwelleth in you?" -- 1 Corinthians 3:16
***17 And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together. ***
If so be that we suffer with him, that we MAY be also glorified...
If you don’t suffer with Him, then you may NOT be glorified together...
Remember the Judgement and those found to be unworthy based upon their deeds who are cast into the abyss created for the devil and all his minions.