because everyone else would say that...

"What would you say the gospel is, Brian?"

I answered by quoting the apostle Paul in the New Testament--statements about justification by grace through faith, the gift of salvation, Christ being a substitutionary sacrifice for me sin. "That's exactly what most evangelicals say," he replied, letting the tension hang for what seemed to me like a long, long time.
The Secret Message of Jesus, p. 91

Ephesians
2:8 for by grace have ye been saved through faith; and that not of yourselves, [it is] the gift of God;
2:9 not of works, that no man should glory.

I Peter
3:18 Because Christ also suffered for sins once, the righteous for the unrighteous, that he might bring us to God; being put to death in the flesh, but made alive in the spirit;

Mark
10:45 For the Son of man also came not to be ministered unto, but to minister, and to give his life a ransom for many.

Romans
5:6 For while we were yet weak, in due season Christ died for the ungodly.
5:7 For scarcely for a righteous man will one die: for peradventure for the good man some one would even dare to die.
5:8 But God commendeth his own love toward us, in that, while we were yet sinners, Christ died for us.
5:9 Much more then, being now justified by his blood, shall we be saved from the wrath [of God] through him.
5:10 For if, while we were enemies, we were reconciled to God through the death of his Son, much more, being reconciled, shall we be saved by his life;
5:11 and not only so, but we also rejoice in God through our Lord Jesus Christ, through whom we have now received the reconciliation.