Read Romans 5:12 Using Other Translations
Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned--
When Adam sinned, sin entered the world. Adam’s sin brought death, so death spread to everyone, for everyone sinned.