(CNN) Republican lawmakers are directly urging President Donald Trump on Thursday to sign a bill to avert a government shutdown, underscoring the uncertainty on Capitol Hill in whether Trump is on board just hours before Congress is supposed to vote on the package.

After the prayer to open the Senate, Sen. Chuck Grassley, Republican of Iowa, said, "Let's all pray that the president will have wisdom to sign the bill so the government doesn't shut down."

As lawmakers prepare to rush the bill through both chambers ahead of a Friday night deadline, it was still unclear whether Trump would surprise Capitol Hill again and oppose its bid to keep the government open.

"I pray" Trump signs the bill, said Sen. Richard Shelby, the Republican chairman of the Appropriations committee. He said he spoke with Trump last night and the president was in "good spirits."

In December, Trump rejected the Senate's short-term bill to keep several federal government agencies, including the Department of Homeland Security, running through February 8, following through on his threats to shut down the government over his request for billions of dollars to build a wall on the US southern border. That decision led to a 35-day partial government shutdown, the longest in US history. Three weeks ago, Trump conceded to public pressure to temporarily reopen the government and pay about 800,000 government workers.

Read More