Verily, verily, I say unto you, He that believeth on Me hath everlasting life. – John 6:47

No man among us doubts that if he had performed the law of God the Lord would give him life; but it is equally certain that if we have believed in the Lord Jesus Christ we have eternal life. No trembling sinner doubts but that by the breaking of the law we are condemned: be you equally sure of it, that by not believing you are condemned. As no keeper of the law would have been lost on any ground whatever, so no believer in Christ shall be lost on any ground whatever; as no breaker of the law could escape punishment, so no unbeliever in Christ can be saved. The gospel states its message as clearly as the law. As positively as the law utters its promise and threat, so positively and unalterably doth the gospel deliver its decree. The believer in Jesus shall be saved because he is a believer; and Christ’s veracity is staked thereon:-“Verily, verily, I say unto you, He that believeth on Me hath everlasting life.”

Oh, but this is a very blessed thing to have to say to you. I do not come to-day with a gospel veiled in mystery and shrouded in doubt; I do not bring a message which you cannot understand or receive; neither do I come with “ifs” and “buts” and “peradventures,” but with this, “Whosoever shall call upon the name of the Lord shall be saved.” “He that believeth and is baptized shall be saved.” “Whosoever believeth in Him hath everlasting life.” …Do not suppose that anything is wanted as to doings or feelings in order to complete the righteousness which is wrought out by the Lord Jesus, and imputed by God to the believer… Confess yourself a sinner; trust in the sinner’s Savior, and you are saved. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1700.cfm