And if by grace, then it is no more of works: otherwise grace is no more grace. But if it be of works, then is it no more grace: otherwise work is no more work. (Rom 11:6)
But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him. (Heb 11:6)
While Rom 11:6 is often abused by Protestant to support the concept of sola fide, as with Rom4:1-8, the apostle Paul is condemning, not good works empowered by God’s grace, but those who, on their own works, attempt to put God into a legal debt.
In the Council of Trent, session 6 chapter 8 (January 1547), we read the following which does a good job of harmonising Heb 11:6 with Rom 11:6:
Chapter viii
In what Manner it must be understood that the Impious is Justified by Faith, and freely
But whereas the Apostle saith, that man is justified by faith, and freely, those words are to be understood in that sense which the perpetual consent of the Catholic Church hath held and expressed; to wit, that we be therefore said to be justified by faith, because faith is the beginning of human salvation, the foundation, and the root of all justification; without which it is impossible to please God (Heb 11:6), and to come unto the fellowship of His sons; but we are therefore said to be justified freely, because none of those things which precede justification, whether faith or works, merit the grace itself of justification. For, if it be a grace, then is it no more by works, otherwise, as the same Apostle saith, grace is no more grace (Rom 11:6). (The Canons and Decrees of the Council of Trent [trans. Theodore Alois Buckley [London: George Routledge and Co., 1851], 35)
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