Romans 3:23
For all have sinned and fall short
of the glory of God.
God says that each of us, both you and I, have sinned. We have each done wrong things like lying, cheating, being envious, hating others. Anytime you do, say or think something which is bad God says it is sin. God says you were born with a want-to to sin, and that your sin must be punished.
Romans 6:23
. . . the wages of sin is death . . .
The death God is talking about means to be separated from Him forever and be sent to a place of punishment forever. God doesn't want you to have to be punished for your sin, so He made a way for you to have your sin forgiven.