President Barack Obama officially nominated Jack Lew to replace Tim Geithner as Secretary of the Treasury onThursday, continuing the overhaul of his second-term cabinet.

“Jack knows that every number on a page, every dollar we budget, every decision we make, has to be an expression of who we wish to be as a nation, our values,” Obama said.

Calling Lew a “master of policy,” the president noted, “I don’t want to see him go” from his current role as White House Chief of Staff, “but my loss will be the nation’s gain.”

Obama also warmly praised the outgoing Treasury secretary, saying “When the history books are written, Tim Geithner’s going to go down as one of our finest secretaries of the Treasury.”

After a sustained round of applause, Geithner thanked Obama for giving him the opportunity to serve, and said that he has “the greatest respect for Jack Lew.”

“He’s committed to defending the safety net for the elderly and the poor,” Geithner said. “He understands what it takes to create the conditions for stronger economic growth and broader economic opportunity. And he understands that to govern responsibly is to govern with a recognition that we have limited fiscal resources.”

Video of the announcement is below:

Lew will receive a much frostier reception when he travels to Capitol Hill for his confirmation hearing. Lew has a strained relationship with congressional Republicans after representing the White House in the contentious 2011 debt ceiling negotiations, and at least one liberal plans to oppose his nomination as well. Vermont senator Bernie Sanders — an independent who caucuses with the Democrats — is promising to oppose Lew’s nomination on the grounds that he is too closely tied to Wall Street.