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).