Summary: The way I usually clarify eternal security is by first explaining that there is a distinction between sonship and discipleship.
The way I usually clarify eternal security is by first explaining that there is a distinction between sonship and discipleship. In other words, our relationship as a child of God never changes, although our fellowship varies according to our experience. My relationship with my earthly father never changes (I will always be his son), but my fellowship has changed many times over the years. This is also true of our heavenly Father. Once we are saved our relationship never alters although there are many times we fail to experience the close fellowship we so greatly desire. In the past there has been much confusion in the Scriptures over so-called proof texts that are thought to describe sonship when they are actually describing discipleship.
This might further be explained as union and communion: you cannot have communion (fellowship) without union (relationship). In fact, this is also true of the ordinances of the church. There should be an experience of salvation (union) before we partake of the Lord’s Supper (communion) and specifically in this order. An unbeliever should not partake of the Lord’s Supper before he has experienced regeneration since the participant would have nothing in common with the Lord or the participants.
This two-fold condition of salvation has often been referred to as standing and state. Your standing is as a son of God, but your state varies according to your fellowship (walk, discipleship). This is the reason eternal security has been subsequently misunderstood over the years. Many are unaware of these two levels that are in operation here (relationship, fellowship).
The very words used to describe our experience of salvation provides us an obvious clue to their meaning; that is, “eternal life” – “everlasting life.” Notice they are not described as “temporary” or “conditional” life. The words used to communicate our new state of existence are thus revealed by their eternality.
One of the most often used proof-texts concerning eternal security can be found in the Gospel of John. Jesus states: "My sheep hear my voice, and I know them, and they follow me: And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand. My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father’s hand" (John 10:27-29).
The Psalmist tells us, "The steps of a good man are ordered by the Lord: and He delighteth in his way. Though he fall, he shall not be utterly cast down: for the Lord upholdeth him with His hand" (Psalm 37:23-24). He goes on to say, "For the Lord loveth judgment, and forsaketh not His saints; they are preserved for ever: but the seed of the wicked shall be cut off. The righteous shall inherit the land, and dwell therein for ever" (Ps. 37:28-29).
Notice that it is God that does the keeping, not us. We do not choose ourselves nor do we save ourselves. God is the one that initiates the salvation experience and it is God who will finish it. Paul explains, “For 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 brethren. Moreover whom He did predestinate, them He also called: and whom He called, them He also justified: and whom He justified, them He also glorified” (Rom. 8:29-30).
The Earnest of the Holy Spirit
We have been given the Holy Spirit as an “earnest” (Eph. 2:14 - “down payment or deposit”) that guarantees our future inheritance. Paul states, "Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of His glory" (Eph. 1:14). Just as a potential buyer would place a down payment on a parcel of land promising a complete transaction, God has given Himself as a guarantee that our salvation will be completed.
The Sealing of the Holy Spirit
During this dispensation the Holy Spirit also takes up permanent residence in the believer. Paul says, "In 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" (Eph. 1:13). As soon as the believer is saved, he is baptized into the body of Christ (I Cor. 12:13). He is then sealed unto the day of redemption “for ever” (John 14:16). Jesus said, “And I will pray the Father, and He shall give you another Comforter, that He may abide with you for ever” (John 14:16). Notice that this sealing of the Holy Spirit is not conditional, but a permanent relationship with the believer ("for ever").
An older pastor once told me that he had never heard of anyone in the Bible who had been saved twice. At what point does someone lose his salvation? Is there a magical line that one crosses? If so, then where is this found in the Word of God? A complete and thorough search of all the passages in the Bible concerning the doctrine of salvation will demonstrate that redemption is a once-and-for-all transaction. Once we begin to talk about “doing” something to lose, or gain, our salvation we enter into the realm of “works” and the Bible specifically tells us that we are not saved nor are we kept by our works. Paul states, “For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast” (Eph. 2:8,9).