Jesus made reference to rules taught by men. So when He said that he was referring to the current religious structure. Are there rules taught by men in today's religious structure? Everyone must agree that the answer is in the affirmative. So how do we know what is just a rule taught by men, and what is a requirement of God.
Lets take a look at the thief on the cross in Luke's gospel;
Let's put aside arguments of proof of heaven, or where the apostrophe should be or it's interpretation. I think we can all agree that Jesus was saying that the thief was 'in'. So what do we know about the thief?
He was a sinner.
He deserved to die for his sins.
He accepted Jesus
He was saved
Could it be that simple?