1 Corinthians 15:1-2:

Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand;

By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain.

See also:

Objection: Healing Cannot Be in the Atonement Because Healing Can Be Lost, but Salvation Cannot Be Lost