Here's Ezra, the Biblical and canon-scholar, and the covenant people confessing their sins, including the sin of mixed marriages and the invitations to false and invasive religions from those mixed marriages. Ez. 9.6ff (ESV).
“O my God, I am ashamed and blush to lift my face to you, my God, for our iniquities have risen higher than our heads, and our guilt has mounted up to the heavens. 7 From the days of our fathers to this day we have been in great guilt. And for our iniquities we, our kings, and our priests have been given into the hand of the kings of the lands, to the sword, to captivity, to plundering, and to utter shame, as it is today. 8 But now for a brief moment favor has been shown by the Lord our God, to leave us a remnant and to give us a secure hold[b] within his holy place, that our God may brighten our eyes and grant us a little reviving in our slavery. 9 For we are slaves. Yet our God has not forsaken us in our slavery, but has extended to us his steadfast love before the kings of Persia, to grant us some reviving to set up the house of our God, to repair its ruins, and to give us protection[c] in Judea and Jerusalem.
10 “And now, O our God, what shall we say after this? For we have forsaken your commandments, 11 which you commanded by your servants the prophets, saying, ‘The land that you are entering, to take possession of it, is a land impure with the impurity of the peoples of the lands, with their abominations that have filled it from end to end with their uncleanness. 12 Therefore do not give your daughters to their sons, neither take their daughters for your sons, and never seek their peace or prosperity, that you may be strong and eat the good of the land and leave it for an inheritance to your children forever.’ 13 And after all that has come upon us for our evil deeds and for our great guilt, seeing that you, our God, have punished us less than our iniquities deserved and have given us such a remnant as this, 14 shall we break your commandments again and intermarry with the peoples who practice these abominations? Would you not be angry with us until you consumed us, so that there should be no remnant, nor any to escape? 15 O Lord, the God of Israel, you are just, for we are left a remnant that has escaped, as it is today. Behold, we are before you in our guilt, for none can stand before you because of this.”