Lamentations 3:29

He putteth his mouth in the dust; if so be there may be hope.

Putting the mouth in the dust is humbling oneself in the dust in hope of mercy or deliverance. It is humble submission and patient waiting in hope. In conviction it is the posture of one brought low by God's law. Seeing himself in the light of God's will, he silences his own claims to virtue, puts his mouth in the dust, and acknowledges his uncleanness.

The verse belongs to God's abundant promises that ought forever to stop all murmuring and doubting. Distrust and faint-heartedness are displeasing to God. He has promised mercy, sympathy, and help in time of need to those who ask in faith without wavering. The same image can also portray humiliating yielding under pressure. It describes abandoning resolve to address the evils of slavery and keeping silent because slaveholders would reject the publications.