How should we reckon ourselves in light of where God finds us?
We should reckon ourselves to be exactly where God finds us: while we were yet sinners. Salvation rests on being justified by Christ's blood through faith, not on our own worthiness, so we acknowledge our sinner state and receive God's judicial declaration that we are just as if we had never sinned.
Les explains that Scripture makes it plain it was while we were yet sinners, and just exactly where God finds us is what we have to reckon ourselves to be. Then in verse 9, being now justified by His blood—through faith in His blood, not by drinking literal blood—we have the power of His shed blood applied to our need. He illustrates God's chemistry: in the physical realm something placed in blood comes out blood red or dark brown, but in God's chemistry, placed in the blood of Christ, it comes out white as new fallen snow. Being justified is God's judicial declaration that we are now just as if we had never sinned—like Adam before he fell, not physically.