The televised speech seemed aimed at establishing the cleric, who leapt to prominence with his fierce criticism of the 2003 US-led invasion, as a figure above the everyday Iraqi political fray.
"Politics became a door for injustice and carelessness, and the abuse and humiliation of the rule of a dictator and tyrant who controls the funds, so he loots them... And the cities, so he attacks them, and the sects, so he divides them," Sadr said.
Sadr called on Iraqis to vote in parliamentary elections that are now a little more than two months away.
Iraqis "must participate in these elections in a major way, so that the government does not fall into the hands of the dishonest," Sadr said.
More From This Section
He also reaffirmed his weekend announcement that he was separating himself from his powerful political movement, which holds dozens of parliamentary seats and six ministerial posts.
"I will remain for all -- not for the Sadrists only, for I dedicated myself to Iraq and to Islam," Sadr said in comments indicating he still could play an influential role in Iraq's political future.
Sadr's rise was aided by the reputations of two famed relatives -- including his father, Mohammed Mohammed Sadiq al-Sadr -- who were killed during Saddam Hussein's rule.
Sadr was also the commander of the Mahdi Army, a widely-feared militia that battled US forces and played a key role in the brutal Sunni-Shiite sectarian conflict in which thousands of people were killed.
He later suspended the militia's activities and in recent years his focus has increasingly shifted to religious studies in both Iran and Iraq that have taken him out of the country for extended periods of time.