PaulThomson said:
Where does it say "used to be sinners"? Which Bible version are you reading?
The us could be various groups Paul is identifies Himself with: The Jews, or the church, or mankind.
If God demonstrated His love to us, by dying for us; and He also died for them; then His death for them demonstrates His love for them.
So, no translation says, "used to be sinners"? Then why did you write those words as if they were scripture that supported your theology. I agree it says "While we were yet sinners..." That does not mean the same thing as "those who used to be sinners".
It si not bad interpretation to admit the range of possible options a text can mean. It could mean either of those things. It is dishonest to pretend it can only be one of those options... the one that best accommodates your own theories.