Assurance and the Law-Gospel Antithesis...

"While no sane man will strike off the yoke of God from the shoulders of believers, as if they behooved not to keep his Commandments, it must still be understood that assurance of salvation by no means depends on the observance of them. For the words of Paul always hold true, that the difference between the Law and the Gospel lies in this, that the latter does not like the former promise life under the condition of works, but from faith. What can be clearer than the antithesis — “The righteousness of the law is in this wise, The man who doeth these things shall live in them. But the righteousness which is of faith speaketh thus, Whoso believeth,” etc. (Romans 10:5.) To the same effect is this other passage,"

“If the inheritance were of the law, faith would be made void and the promise abolished. Therefore it is of faith that in respect of grace the promise might be sure to every one that believeth.” (Romans 4:14.)

John Calvin, Acts of the Council of Trent with the Antidote