He told the media here that he quit Friday "to put an end to unnnecessary controversy" regarding allegations of interference in the CBI's probe into the coal blocks allocation.
He insisted that the Supreme Court had made no adverse comments against him.
"My conscience remains clear and I believe I will stand vindicated because divine justice ordains that truth and justice will prevail."
Mumbai Roundup: 9 incidents that took place this week
Photos: Ajay Devgn, Parineeti, Tabu at 'Golmaal Again' trailer launch
Photos: Dipika Pallikal Karthik oozes oomph in bikinis and sarees
Photos: Kareena Kapoor Khan's grand birthday bash
Photos: 'Dangal' girls Sanya Malhotra, Fatima Sana Shaikh's dinner outing