Here is a note from the commentary I am reading this morning: "Drawing upon the theology of Dietrich Bonhoeffer, Thronveit remarks that Ezra's prayer/speech 'speaks against the attitude of cheap grace that has counted on God's continual provision but has failed to heed the warnings of scripture or history". -Matthew Levering, Ezra & Nehemiah, Brazos Theological Commentary, p. 102.
As I am reading Ezra and being aided in my reflections by this commentary, it is brought out to me how clearly Ezra looked to scripture and to God's working in history. He understood Israel's exile in terms of God's judgment as the book of 1 & 2 Kings does, and he understood the return of the remnant as a fulfillment of Jeremiah's prohecy of return after 70 years of captivity. He also saw God's providential working in the leniency of the Persian kings who allowed the Israelites to return and facilitated their rebuilding of the temple, and he was afraid that the Israelites intermarriage with idolatrous peoples around them would bring about the same judgment on Israel as that recounted in 1 & 2 Kings in which both Judah and the Northern Kingdom, after hundreds of years of flagrant idolatry, finally are discarded. But this time, Ezra fears, the judgment may be more final. He rips his hair and beard, and rends his clothing. He sees God in history, and leads all Israel into communal confession of sins.
It is interesting to think of cheap grace in reference to our understanding of God working in history and in our relationship to the Scriptures. If the Scriptures cannot demand anything of us, except when morphed into human principles, then it is cheap grace. Similarly, if we do not see God at work in history and in our times, in our lives and in the broader world, then it is cheap grace.