New Wine & Old Wineskins
Another common translation of this study word "lost" is "to ruin or be ruined." When Jesus describes the difference between the life before and after repentance, He uses this word. He compares the two lives to wineskins:
17Neither do people put new wine into old wine skins, or else the skins would burst, and the wine be spilled, and the skins ruined. No, they put new wine into fresh wine skins, and both are preserved.” Matthew 9:17
The disciples weren't ready for the totality of life in the Kingdom because they had yet to enter into total repentance and dependence upon Christ. They couldn't be expected to fast as John's disciples (Matthew 9:14-15), while they were still learning of the Lord and what He required of them.
If the new wine of His life was poured into them then, they would burst, the wine poured out, and their "wineskins" ruined. Here the word "to perish" (ruined) is in the future middle indicative form, meaning it will happen and the skins do it to themselves. If the new wine is put into old wineskins, the skins will burst, the wine will be spilled and the skins will ruin themselves.
However, the first two actions are passive, meaning it happens to them rather than them doing it to themselves: the skins burst (by way of the new wine causing them to expand), the wine is spilled (because the skins expand and cannot hold it).
Jesus compares His Word to wine, because that was the subject—why the disciples weren't doing as John's disciples did. The Lord responded that it was due to Him still being with them; they were still receiving from Him, and were not ready to act as the others. His wine would be "poured out" (εκχειται) if they were to receive it now—He had to wait until they had become new.
Once there were new skins then the new wine could be "cast" (βαλλουσιν) into them and both "would be preserved" (συντηρουνται). That last Greek word comes from words meaning "with" and "watch, guard, discern, observe." To preserve, then, is almost to observe with, in order to keep something safe. When the disciples were to become new creations through their faith in Jesus and His resurrected self, they would be able to hold the new wine of His Word. Then both—His Word and their own selves—would be preserved!
But the fact that the old skins would be ruined is contributed to by the skins themselves. Being in the middle voice, one could translate it, "the skins will ruin themselves."
Thus we can see again that it is people themselves who are contributing to their own destruction. It is not done to them, but they play a role in causing it to happen. Just as the disciples "were causing themselves to die" in the boat amidst the storm (Matthew 8:25), so these old wineskins would "cause themselves to be ruined" if they were to hold new wine.
This seems to compare with Jesus' other admonition neither "to throw what is holy to the dogs, nor cast our pearl before swine."
6“Don’t give that which is holy to the dogs, neither throw your pearls before the pigs, lest perhaps they trample them under their feet, and turn and tear you to pieces. Matthew 7:6
This is a dangerous proposition of which all believers need to be aware. Not everyone is ready, or willing, to receive the things of God. Those who are yet old in their sins, who are not ready to receive the teachings of Christ, simply are unable to hold this new wine. As old wineskins, they were worn and unable to support the fermenting of new wine (as old wine was already fermented). They would simply burst when the new wine fermented.
The truths of Yahweh are reserved for those who believe in Him—dogs in scripture represent unbelievers, those actively rejecting His truth and authority. Pigs or swine represent the unclean, those who are not right before Him. These groups of people should not be given the new wine of Christ's teaching, because they are so contrary to God that they will both trample it underfoot at the same time as charging us intending to tear us to pieces.
Clearly there are various stages of such unbelief—for we know the disciples, although yet unbelieving in many ways, were gradually coming to trust Jesus more and more. Even so they are termed old wineskins yet unable to receive the new wine. How much more so for those who adamantly reject the revelation of God!
How does this connect with this more broad teaching of being lost and found? Knowing the word "lost" is also translated "ruined," we can compare this ruining of the old wineskins if they were to receive new wine, with destroying oneself if receiving the things of God before one is ready.
Just as Jesus shows in His parable about the seed and the various soils, those with rocky hearts, no place for the word at all, or those that do not tend their ground will not allow the seed to bear fruit (Matthew 13:3-9). Either it is taken away by Satan before having a chance to grow (that by the roadside), it springs up immediately but withers when the sun rises due to having no root (rocky ground), or it is choked by the many cares of this age (thorny ground) (Matthew 13:16-22). In all of those cases, the old wineskins are not ready to bear the new wine and both the wine is spilled and the skins "ruined."
Thus, prepare your heart and consider whether you have truly come to a place of repentance. Have you chosen to leave behind the ways of this age? Have you decided to listen to Jesus and follow Him? Have you placed your life into His hands, confessing that He is your Lord and Savior? If so, you have been born again, transformed into a new wineskin, able to hold the pouring of His new wine into your life. If not, you will only destroy yourself by trying to receive His things. You would be better off keeping the old wine of the ways of this world inside. Therefore, choose Him, be transformed and so prepare yourself for His new things!