Former President Barack Obama reportedly warned freshman Democrats this week on the cost of their sweeping proposals, urging them to figure out how to pay for them.

Obama, who has largely stayed out of the public eye since leaving office, encouraged a group of freshman Democrats to continue to pursue “bold” ideas, according to The Washington Post, but also to home in on the details of funding them.

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“He said we [as Democrats] shouldn’t be afraid of big, bold ideas – but also need to think in the nitty-gritty about how those big, bold ideas will work and how you pay for them,” one person familiar with Obama’s remarks told The Post.

While the former president did not call out any specific proposals by name, some reportedly took his advice as a note for those new lawmakers pushing "Medicare-for-all" and the Green New Deal—both liberal policies popularized by House freshmen, including Rep. Alexandria Ocasio-Cortez, D-N.Y.

The Green New Deal is a massive overhaul of the nation’s economy and energy use, with an estimated cost that could reach well into the tens of trillions of dollars. The resolution, which is nonbinding, is co-sponsored by nearly all major 2020 Democrats in Congress and was introduced in the House last month.

The rollout of the proposal caused headaches for Democrats, as it included FAQs from Ocasio-Cortez containing promises of economic security for those “unwilling to work” and talk of abolishing air travel in favor of high-speed rail. But Ocasio-Cortez has not yet explained a plan for how to fund the program.

Meanwhile, Senate Majority Leader Mitch McConnell on Tuesday will put the Green New Deal to a test vote, in a move that will force Democrats to take an official stand on the measure and pit the party’s moderate members against its progressive wing.

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Obama, later, reportedly encouraged the freshman lawmakers to find a policy and fight for it. The Post said Obama said that The Affordable Care Act, or ObamaCare, was the policy that Obama said he was willing to lose his office over. Obama also reportedly talked about the importance of working with constituents and “staying in touch” with them.

But while Obama is typically a unifying voice in the Democratic Party, freshman Rep. Ilhan Omar, D-Minn., has criticized the former president in recent weeks, reportedly suggesting in an interview his message of “hope and change” is a “mirage.”

“Recalling the ‘caging of kids’ at the U.S.-Mexico border and the ‘droning of countries around the world’ on Obama’s watch," Omar charged that Obama "operated within the same fundamentally broken framework as his Republican successor,” the recent article in Politico said.

Omar later claimed she was misquoted by Politico, tweeting that she is a fan of Obama. But the move immediately backfired as the recording of her interview confirmed the comments she made to the news outlet. She later deleted her tweet.

Fox News' Adam Shaw and Lukas Mikelionis contributed to this report.