Whosoever will candidly consider each particular, will recognise the greatness of the gifts which were given by him.129 For from him130 have sprung the priests and all the Levites who minister at the altar of God. From him also [was descended] our Lord Jesus Christ according to the flesh.131 From him [arose] kings, princes, and rulers of the race of Judah. Nor are his other tribes in small glory, inasmuch as God had promised, "Thy seed shall be as the stars of heaven."132 All these, therefore, were highly honoured, and made great, not for their own sake, or for their own works, or for the righteousness which they wrought, but through the operation of His will. And we, too, being called by His will in Christ Jesus, are not justified by ourselves, nor by our own wisdom, or understanding, or godliness, or works which we have wrought in holiness of heart; but by that faith through which, from the beginning, Almighty God has justified all men; to whom be glory for ever and ever. Amen.
As can be seen from this quote St. Clement believed and taught JBFA as well. Clearly he says we are not justified by ourselves, this completely negates anything in us - our good works or following or "doing" any commandments, even works brought about by the "purity" of heart.
Now some will jump and probably point out to me - hey look at Chapters 33-35 where he talks about works, as if St. Clement just contradicted himself! Yes he does talk about works, but Chapter 32 as preamble eliminates any works as source of justification instead it speaks of faith through which God has justified all men and I quote but by that faith through which, from the beginning, Almighty God has justified all men; to whom be glory for ever and ever. Chapters 33-35 should be read in context - and what surrounds the discussion. Proof of this is in looking at Chapter 36 where all gifts are given by God to us for the sake Christ.
St. Clement in my thinking was following the Apostle Paul in his exposition like that in Romans. After discussing the free grace of God in justifying us in Christ in Romans 3,4,5, St. Paul talks about holiness , and good works in Romans 6. To me this is one example of a convincing evidence that what the Reformers taught was not new, but was believed by the early Christians before.
I noticed that St. Clement quotes a lot from the writings of OT and NT, and this was writen in Koine Greek, I hope to read it in that language for practice one day.