A man asked Jesus if those who would be saved would be few. Jesus' response is key to understanding that salvation requires effort:
Luke 13:23 Now a man said to him: “Lord, are those being saved few?”
He said to them: 24 “Exert yourselves vigorously to get in through the narrow door, because many, I tell you, will seek to get in but will not be able...."
Salvation will be obtained when those who have survived the great tribulation are allowed to pass alive into God's new world:
Rev. 7:9 After this I saw, and look! a great crowd, which no man was able to number, out of all nations and tribes and peoples and tongues, standing before the throne and before the Lamb, dressed in white robes; and there were palm branches in their hands. 10 And they keep shouting with a loud voice, saying: “Salvation we owe to our God, who is seated on the throne, and to the Lamb.” (...) 13 In response one of the elders said to me: “These who are dressed in the white robes, who are they and where did they come from?” 14 So right away I said to him: “My lord, you are the one who knows.” And he said to me: “These are the ones who come out of the great tribulation, and they have washed their robes and made them white in the blood of the Lamb. 15 That is why they are before the throne of God, and they are rendering him sacred service day and night in his temple; and the One seated on the throne will spread his tent over them. "
... and then the angel told John why they can talk about being saved:
Rev. 14:16 "They will hunger no more nor thirst anymore, neither will the sun beat down on them nor any scorching heat, 17 because the Lamb, who is in the midst of the throne, will shepherd them and will guide them to springs of waters of life. And God will wipe out every tear from their eyes.”
Until that moment no one own "salvation":
Matt. 24:13 But the one who has endured to the end will be saved.