Here is some quotes and URLs from a number of sources on the Sessions lying issue:
“The good news for Sessions is that he can plausibly claim to have opposed any Russian collusion,” writes the New Republic‘s Jeet Heer. “The bad news is that, in making those claims, he opens himself up to charges of perjury.”
From October 18, 2017 Senate Judiciary Hearing (oversight hearing)
Franken: “You don’t believe that surrogates from the Trump campaign had communications with the Russians?”
Sessions: “I did not — and I’m not aware of anyone else that did. I don’t believe that it happened,”
This is from the Oct. 18, 2017 hearing and is perhaps the most clear lie that Sessions told under oath.
Sessions was present at the March meeting with Papadopoulos in which Papadopoulos said he could arrange a meeting between Putin and Trump according to the Papadopoulos' legal plea document. (Note this is documented.)
According to sources, Sessions spoke up at this meeting saying this should not be discussed.
Regardless of your belief in the "sources", it is unlikely that Sessions forgot this meeting. Ergo, he lied.
Oh! Sessions suddenly remembers what he couldn't recall in his testimony. Appears the threat of perjury jogged his memory.
https://www.vanityfair.com/news/2017/11/jeff-sessions-george-papadopoulos-russia
Now, however, Sessions has reportedly changed his tune. Citing a source familiar with Sessions’s thinking, NBC News reported on Thursday that the attorney general—who served as a top Trump surrogate and headed the then-presidential hopeful’s national security team—does in fact recall rejecting George Papadopoulos’s offer to arrange a meeting between Trump and Putin, after the Republican candidate stopped short of ruling out the idea.
“The March 31 comments by this Papadopoulos person did not leave a lasting impression,” the source told NBC News. “As far as Sessions seemed to be concerned, when he shut down this idea of Papadopoulos engaging with Russia, that was the end of it and he moved the meeting along to other issues.” The source added that Papadopoulos was viewed by those in attendance “as someone who didn't have a lot of credibility.”
What’s amazing about this is that someone in the Trump administration is pitching this clear evidence of Sessions’s perjury as an alibi against what seems like proof of collusion. The “vehement” opposition to a meeting with Putin that Sessions allegedly expressed makes it much harder to argue that he had no recollection of surrogates talking to the Russians. And they’re hardly doing the president a huge favor in portraying him as open to the idea. Who are they trying to protect?
https://washingtonmonthly.com/2017/11/01/trumps-defense-is-that-sessions-perjured-himself/