Matthew 16: 25-26 For whosoever will save (4982 save, rescue, heal) his life shall lose (622 lose, destroy, abolish) it: and whosoever will lose his life (5590) for my sake shall find (2147 discover or recognize) it. For what is a man profited , if he shall gain the whole world, and lose (622 lose, destroy, abolish) his own soul? or what shall a man give in exchange for his soul (5590)? Please note that the same Greek word translates life and soul in this verse.
Mark 8: 35-36 For whosoever will save (4982 save, rescue, heal) his life shall lose (622 lose, destroy, abolish) it; but whosoever shall lose (622 lose, destroy, abolish) his life for my sake and the gospel's, the same shall save(4982 save, rescue, heal) it. 36 For what shall it profit a man, if he shall gain the whole world, and lose (2210, damage) his own soul? 37 Or what shall a man give in exchange for his soul?
Luke 15:4 What man of you, having an hundred sheep, if he lose (622 lose, destroy, abolish) one of them, doth not leave the ninety and nine in the wilderness, and go after that which is lost , until he find (2147 discover or recognize) it?
Luke 15:24 For this my son was dead (3498 inoperative, deceased) , and is alive (326 restored, revived) again ; he was lost (622 lose, destroy, abolish) , and is found (2147 discovered or recognized). And they began to be merry.
The concept of loss has some prominence in the NT words of Jesus and subsequently in Christian theology. In fact the status of being lost in the church's understanding means subject to God's wrath and doomed to eternal punishment. The verses above are primary examples of Jesus teaching about loss, in parables and otherwise. The notes in parentheses after the emboldened words come from Strong's Concordance.
Interestingly, in each account above, the picture of loss does not involve rejection and condemnation by anyone. Most take the shepherd in Luke 15:4 to represent Jesus and the Father in Luke 15: 24 to be God. In each example the lost state is initiated by the lost one. The shepherd and the father both actively desire the restoration of the one who is lost. In the words of the father of the prodigal son, the state of loss is a death and the state of being found involves a resurrection of some sort.
The actions of the shepherd and the father in the stories cited raise serious questions in relation to Orthodox theology's depiction of being lost, meaning under God's condemnation and subject to divine wrath. The shepherd who insists on having 100% of his sheep and the father who passionately welcomes the prodigal home do not easily reconcile with a picture of a God who damns eternally.
Now, the Orthodox will likely insist that the 100% merely insures that all true believers will be eternally secure. However, in assuming that the sheep of Luke 15:4 represent only the righteous, they by implication invoke Matthew 25:32-46 where we see described a judgment according to works. Since Christian Orthodoxy denies salvation by works, they can hardly use this sheep versus goat distinction to limit Luke 15:4's application to their definition of true believers.
If they want to claim that Matthew 25 merely calls attention to the benevolent actions which only true believers display, meaning that the doctrinal conformity of the sheep is what allowed them to perform the required works, they must answer why we all see benevolence out of many who are not church affiliated. In fact, many churches encourage their members to only engage in acts of benevolence through the church, claiming that this gives God the glory and credit for such works. This encouragement basically concedes the point that good works are not just the product of the church member.
Similarly, if the Orthodox note that the prodigal son did not enjoy the blessing of the father until he made the right, first move, they must also contend with the evident fact that there is not one note of condemnation in the reaction of the father to the son's lost state, either before or after his return. In fact, the father rejects the condemnation of the older son as inappropriate. Likewise, there is no indication that physical death could have changed the father's mind about his love for his son.
Yes, Jesus taught about a state of being lost. That lost state involved loss of life and loss of the soul. Loss in each case meant to damage one's spiritual/emotional well being, during our physical existence. That damage occurred because of self centeredness and did not involve divine rejection.
We all know that there is a difference between being a lost soul in the sense of losing one's way and being a lost soul in standard church theology. In the Bible examples I remain lost only until the shepherd finds me and I find my way back home. In neither case am I doomed to being lost forever.