Matthew 10:16-22
16 Behold, I send you forth as sheep in the midst of wolves: be ye therefore wise as serpents, and harmless as doves.
17 But beware of men: for they will deliver you up to the councils, and they will scourge you in their synagogues;
18 And ye shall be brought before governors and kings for my sake, for a testimony against them and the Gentiles.
19 But when they deliver you up, take no thought how or what ye shall speak: for it shall be given you in that same hour what ye shall speak.
20 For it is not ye that speak, but the Spirit of your Father which speaketh in you.
21 And the brother shall deliver up the brother to death, and the father the child: and the children shall rise up against their parents, and cause them to be put to death.
22 And ye shall be hated of all men for my name's sake: but he that endureth to the end shall be saved.
Charles Bing - Grace, Salvation, and Discipleship - He Who Endures to the End, Matthew 24:13 (cf. Matthew 10:22; Mark 13:13; Luke 21:19)
(Salvation) Interpretation: Only someone who continues in good works and faith to the end of his life will receive salvation or prove he was saved.
(Discipleship) Interpretation: Only those of Israel in the Tribulation who are able to endure persecution until the time of Christ's return will be delivered from the hostile nations.
This saying in Matthew and Mark is used by some to teach that professing Christians must persevere in faith and good works in order to prove their salvation is genuine, which is a (Salvation) interpretation.
While those who say professing Christians must persevere in order to prove that they are genuinely saved, they would not admit that perseverance is a work that earns salvation. Of course, this is flawed reasoning, because if perseverance is necessary to prove salvation, then perseverance is necessary for salvation. This is in addition to one's initial faith in Jesus Christ as Savior. Salvation would be by faith plus one's performance, which contradicts the free nature of God's grace. Some might try to avoid this charge by modifying their view to say that true saving faith is a faith that performs, but this does not avoid the error of making works necessary for salvation.
The (Salvation) interpretation understands "the end" to mean the end of one's physical life. But this ignores the unique order and events of the end times about which Jesus is speaking. The context indicates what "the end" refers to. It is clear that Matthew (and Mark) is speaking about conditions in the time of Israel's great Tribulation (which also seems to be the context of a similar saying in Matt. 10:22). In answering the disciples' question about His return (Matt. 24:3), Jesus answers the last question about the end of the age first. When Jesus refers to "the end" in verses 6, 13, and 14, it has the same meaning - the end of the age which concludes with the Tribulation period. In that time of great sorrow, the Jews will be hated and killed by all the nations (Matt. 24:9), betrayed by their own countrymen (Matt. 24:10), deceived by false prophets (Matt. 24:11), and experience lawlessness and lack of natural affection (Matt. 24:12). After verse 13, Jesus' prophecy reveals the details that actually describe His coming (Matt. 24:14-51). Though many of Israel will be killed, those who endure these perils to the end of the Tribulation (not to the end of their physical lives, which is the (Salvation) interpretation) will be delivered ("saved") from their enemies, the nations who hate them. This "last minute rescue" of Israel by Jesus Christ is a clear biblical prophecy (Zech. 12:2-9; Rom. 11:26). This is an example of the word saved referring to deliverance from a danger, not deliverance from hell. Indeed, hell is not mentioned in the passage. This is obviously (Discipleship) because enduring to the end does not relate to eternal salvation but temporal deliverance of God's people. In verse 22, Jesus says, "And unless those days were shortened, no flesh would be saved..." It appears that "no flesh" includes Gentiles among those delivered. The parable of the sheep and goats in Matthew 25:31-46 shows that Gentiles ("nations") will be present at the end of the Tribulation.
Israel's story is a story of God's grace. They were chosen by Him to be a special people. In spite of constant sin, God preserved them throughout their history. He will preserve them in the future as well, not because they deserve it, but because He is faithful to His promise to do so. We who are saved by God's grace are kept saved by grace, and will be glorified ultimately and finally by His grace, not because we deserve it, but because that is God's promise to all who believe (John 3:16; 5:24; Rom. 8:28).
Thomas Constable's Expository Notes on the Bible - Matthew 10:21-22
10:21 The disciples would find themselves opposed by everyone without distinction because of their identification with Jesus, including their own family members, not just rulers. Some of them would even be put to death. Of course none of the Twelve died before their present mission was over. This is another evidence that Jesus was speaking about future disciples of His and not just the Twelve.
10:22 In spite of such widespread and malicious persecution, the disciple must endure patiently to the end. "The end" refers to the end of this period of intense persecution, including the Tribulation (cf. Matthew 24:13). The Second Coming of the Son of Man will end the Tribulation (v. 23). The promise of salvation ("will be saved," v. 22) for the one who remains faithful (endures "to the end"), does not refer to eternal salvation, since that depends on faith in Jesus alone. It is deliverance from the intense persecution that is in view. Entrance into the earthly millennial kingdom would constitute salvation for future persecuted disciples in the Tribulation.
This verse does not say that all genuine believers will inevitably persevere in their faith and good works, as some have believed. Rather, it says that those who do, during the Tribulation, can expect God to deliver them at its end. Jesus was not speaking about eternal salvation but temporal deliverance. Temporal deliverance depended on faithful perseverance. Whereas "the end" has specific reference to the end of the Tribulation in Matthew 24:13, here it probably has the more general meaning of "as long as may be necessary."