Do we have to work for salvation?

No. Salvation is not something we achieve through labor or effort; it is entirely a gift from God. The wages of sin is death, but salvation is a gift of God. Therefore, we do not work for salvation at all.

Les teaches that salvation is not something we work for; it is totally a gift of God. He emphasizes this repeatedly as he resumes 1 Corinthians chapter 3, where the context is the whole idea of reward. He contrasts the wages of sin, which is death, with salvation, which is a gift of God. So while there may be rewards for service, salvation itself is not earned by works.

Romans 6:23

For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.

Do we work for salvation or is it a gift from God?

Salvation is not earned by works; it is totally a gift of God. The wages of sin is death, but salvation is a gift of God. Therefore, no one works for salvation as a wage; it is received as God's gracious gift, not as something earned by human effort.