I came across a very helpful article concerning legalism in the New Testament's historical books. Derrick Olliff is the author, and has many well reasoned arguments.
His main thesis states that "there was no significant criticism of Israel or the Pharisees for merit legalism." He adds that, "Israel and the Pharisees were consistently and significantly criticized and judged for other things: antinomianism/hypocrisy and unbelief." And oddly enough he writes, "The views that sound the most like merit legalism to us came from Jesus, and the New Testament records a number of instances where Jesus taught such views."
I especially appreciated this prophetic statement,
"if a Protestant today said some of the things that Jesus said, he would have some splainin' to do. In fact, I have heard talks from Reformed Christians that either included material quite similar to Jesus' words above or that were less easily confused with merit legalism, and those talks have been condemned for supposedly advocating works righteousness, justification by faith plus works, or something similar."
Olliff's study of the gospels and Acts is a very helpful one and does a remarkable job of recalibrating one's understanding.