Former House Speaker Paul Ryan has emerged from retirement with a rare statement to weigh in on the controversy surrounding the certification of the electoral college votes this week, emphasizing that “voters determine the president” while warning “this self-governance cannot sustain itself if the whims of Congress replace the will of the people.”

“Efforts to reject the votes of the Electoral College and sow doubt about Joe Biden’s victory strike at the foundation of our republic,” Ryan noted. “It is difficult to conceive of a more anti-democratic and anti-conservative act than a federal intervention to overturn the results of state-certified elections and disenfranchise millions of Americans.”

Ryan added that the Trump campaign had “ample opportunity” to challenge the results but failed “from lack of evidence.”

"The legal process was exhausted, and the results were decisively confirmed. The Department of Justice, too, found no basis for overturning the result. If states wish to reform their processes for future elections, that is their prerogative. But Joe Biden’s victory is entirely legitimate.”

-ABC News' John Parkinson

From the bipartisan group who hammered out the COVID relief compromise, an appeal to senators to accept the Electoral College results, writing in a statement, " It is time to move forward."

Sens. Joe Manchin, D-W.Va., Susan Collins, R-Maine, Mark Warner, D-Va., Bill Cassidy, R-La., Jeanne Shaheen, D-N.H., Lisa Murkowski, R-Alaska, Angus King, I-Maine, Mitt Romney, R-Utah, Maggie Hassan, D-N.H., and Dick Durbin, D-Ill., issued the following statement on the upcoming Congressional certification of the 2020 Presidential election results: 

"The 2020 election is over. All challenges through recounts and appeals have been exhausted. At this point, further attempts to cast doubt on the legitimacy of the 2020 Presidential election are contrary to the clearly expressed will of the American people and only serve to undermine Americans' confidence in the already determined election results. The voters have spoken, and Congress must now fulfill its responsibility to certify the election results. In two weeks, we will begin working with our colleagues and the new Administration on bipartisan, common sense solutions to the enormous challenges facing our country. It is time to move forward."

-ABC News' Trish Turner

With all new senators having been sworn in, Majority Leader Mitch McConnell welcomed the new members on the Senate floor.

"To say the 117th congress convenes at a challenging time would indeed be an understatement. From political divisions to a deadly pandemic to adversaries around the world the hurdles before us are many and they are serious, but there are also plenty of reasons for hope," McConnell said.

The Senate also passed a series of administrative resolutions and standing orders for the new Congress -- including an agreement to Wednesday as a the date to count electoral votes. It's a date already set, but this formalizes it. 

In his welcoming remarks, McConnell urged members to remember their oath to the Constitution. 

"We gavel in today like 116 prior Senates have gaveled in before us with plenty of disagreements and policy differences among our ranks but all -- all swearing the same oath to support and defend the same Constitution," McConnell said. "All loving the same country and all of us committed to do what we can to leave behind an even stronger nation than the one we've been blessed to inherit."

The Senate stands adjourned until Wednesday.

-ABC News' Allison Pecorin

Wisconsin Democrat Rep. Gwen Moore will participate in Sunday’s opening day events –- including the House speaker’s vote, according to her office, after testing positive for COVID-19 just six days ago.

Republicans complained that her presence “certainly seems to be in violation of the (Office of the Attending Physician) quarantine guidance,” and wonder how it was safe for her to travel to Washington after her diagnosis.

A senior Democratic aide did not immediately respond to an inquiry questioning whether special accommodations were being made for Moore, whose office also has not yet answered inquiries regarding how she traveled to Washington following her infection.

One Democratic member, who said he received his first dose of the COVID-19 vaccine last Tuesday, told ABC News that he is “staying clear of everyone,” pivoting to observe that some Republicans are at the Capitol and not wearing masks. 

Speaker Nancy Pelosi, whose path to the speakership is narrow with such a slim majority in the new Congress, will depend on Moore’s support to keep her position.

After opening the 117th Congress with the prayer and pledge, the House has initiated a quorum call to establish sufficient attendance ahead of the vote for speaker later in the afternoon. Lawmakers are appearing in groups of 72, arranged by alphabetical order of their last names.

-ABC News' John Parkinson and Benjamin Siegel