God is holy and righteous. We are all sinners and cannot save ourselves by good works, religion, or effort.
“For all have sinned, and come short of the glory of God.” Romans 3:23

Because God loves us, He sent His Son. Jesus Christ is God in the flesh, fully God and fully man. He lived a sinless life we could never live.

Jesus died on the cross for our sins, shedding His precious blood as full payment.
“Christ died for our sins according to the scriptures;
And that he was buried, and that he rose again the third day according to the scriptures.”
1 Corinthians 15:1-4

His resurrection proves the payment was accepted. Sin is paid for. Death is defeated.

Salvation is a free gift, not earned.
“For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
Not of works, lest any man should boast.” Ephesians 2:8-9

When you believe the Gospel, God credits you with His righteousness.
“Therefore being justified by faith, we have peace with God through our Lord Jesus Christ.” Romans 5:1

You are forgiven forever, sealed by the Holy Spirit, and made a child of God.
“There is therefore now no condemnation to them which are in Christ Jesus.” Romans 8:1

The response God asks for is not works, promises, or reform but faith.
“This is the work of God, that ye believe on him whom he hath sent.” John 6:29

If you believe this Gospel, you are saved now and eternally.
“These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life.” 1 John 5:13

Grace alone.
Christ alone.
Faith alone.