Eph 1:5 Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will,
The word predestinated here is related to declared in Romans 1:4 (see comments on Romans 1:3-4). There, it is ὁρίζω – horizo, while here it is from προορίζω – proorizo. In Romans 1:4, Paul is speaking of how the resurrection of Christ was planned and fulfilled. Our spirit has been reborn, but we must wait for the body to be reborn. Hence pro is added onto horizo to make it predetermined. The mistake that is easy to make here is to suggest that the adoption is referring to the complete work of salvation of man.
The adoption referring strictly to the redemption of the body as defined in Romans 8:23.
10And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness.
11But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you.
12Therefore, brethren, we are debtors, not to the flesh, to live after the flesh.
13For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.
14For as many as are led by the Spirit of God, they are the sons of God.
15For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption, whereby we cry, Abba, Father.
16The Spirit itself beareth witness with our spirit, that we are the children of God:
17And 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.
18For I reckon that the sufferings of this present time are not worthy to be compared with the glory which shall be revealed in us.
19For the earnest expectation of the creature waiteth for the manifestation of the sons of God.
20For the creature was made subject to vanity, not willingly, but by reason of him who hath subjected the same in hope,
21Because the creature itself also shall be delivered from the bondage of corruption into the glorious liberty of the children of God.
22For we know that the whole creation groaneth and travaileth in pain together until now.
23And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, the redemption of our body.
24For we are saved by hope: but hope that is seen is not hope: for what a man seeth, why doth he yet hope for?
25But if we hope for that we see not, then do we with patience wait for it.
The whole passage in Romans speaks of the anticipation of the resurrection. Ephesians 1 speaks of the anticipation of the purchased possession sealed by the Spirit (Ephesians 1:14).
One is not predestined to salvation, but to the resurrection of the body after he has been saved. Our salvation is determined upon our spirit after that we believed, and our physical resurrection was predetermined for the future.
11In whom also we have obtained an inheritance, being predestinated according to the purpose of him who worketh all things after the counsel of his own will:
12That we should be to the praise of his glory, who first trusted in Christ.
13In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise,
14Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.