How could something that took place 2,000 years ago be relevant for me today?
It is relevant because God Himself was on the cross, and God is eternal; 2,000 years is like a snap of the finger to Him. Therefore Christ's death, burial, and resurrection is almost contemporary with us, and every believer's old Adam was crucified with Him.
Les explains that this is a logical question many people ask. It has everything to do with us today because it was God Himself who was there on the cross. Since God is eternal, 2,000 years is like a snap of the finger to Him, so Christ's death, burial, and resurrection was almost contemporary with us. Coming back to Romans 6:6, our old man, old Adam, or old sin nature is crucified with Him. The "with Him" is the crucial part: when Christ died on that Roman cross, God saw every believer of all the ages in Christ.
Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin.