Radical acceptance is the idea of taking what you have(in your life and in your brain) for what it is and accepting it without judgement. By no means is this easy to do, I counsel people to do it all the time while I myself am very, very guilty of judging my own feelings and judging people in my life.However, when it is possible, it can be an incredibly freeing thing. So now you are thinking, Emily, you said this had to do with Judaism, how in the world does this have to do with Judaism?
B'tzelem Elohim literally means "in the image of God." Humans, according to Genesis, were made in the image of God. This one of my favorite Jewish ideas in general, but I think it can be especially helpful in the use of Radical Acceptance(see, I told you that they would connect). We need to remember that all of us, even the anxious parts and the parts that we like to pretend don't exist, are in the image of God. Accepting ourselves is a lifelong pursuit, but I think remembering that you are made in the image of God can help quite a bit.
Remembering that every other person in the world, even the ones who we think that we hate, are also made in the image of God is also an important takeaway from these two concepts. No person is less than a person, not even the ones who do things that are absolutely terrible. And every person, even the ones who seem like purely terrible people "contain multitudes," and are more complicated than they seem. We need to keep this in mind with our friends, our enemies, our mentors, and anyone who are in danger of seeing from a one-sided perspective regardless of whether or not we believe in God.