I've said it before, that Rev Laura Lin's CCCNY is the best example I've found, if one is studying the process of how liberal churches like PCUSA and Unitarians come to be.
What troubled me was I could not find any correlation between CCCNY and Redeemer until now, during one of Mefferd's talk show with Tim Littleton where Tim Keller's progressive involvement with groups such as ReVoice is becoming more pronounced.
I thought to myself, why wouldn't Keller care more for his sheep than privately experimenting sleeping with the LGBT community, then it hit me...
Supererogation...thus the sin the likes of Keller and Lin share!!! They are more doing more than they should and doing things they ought not and not doing things they ought!