Circumcised, Yet Uncircumcised

Galatians 5:6
For in Christ Jesus neither circumcision nor uncircumcision means anything, but faith working through love.
As I was reading the Old Testament verses on circumcision, I read this one in Jeremiah:
Jeremiah 9:25-26
"Behold the days are coming," declares the Lord, "that I will punish all who are circumcised and yet uncircumcised--Egypt, and Judah, and Edom, and the sons of Ammon, and Moab, all all those inhabiting the desert who clip the hair on their temples; for all the nations are uncircumcised, and all the house of Israel are uncircumcised of heart."
In looking at the cross references for Jeremiah 9:26, I found one from Leviticus, referring to the "uncircumcised of heart" part of that verse. I couldn't remember ever noticing anything about "uncircumcised of heart" in Leviticus, the book with all those laws, so I looked it up.
The cross reference is Leviticus 26:41, but to understand the context, I skimmed through Leviticus 26 up to that verse. It is the parallel of Deuteronomy 28 with the blessings for obedience and the curses for disobedience. In verse 40, there is the beginning of a message of hope. Although God's chosen people disobey, they have a second chance. Here's verse 41:
Leviticus 26:41
41 I also was acting with hostility against them, to bring them into the land of their enemies--or if their uncircumcised heart becomes humbled so that they then make amends for their inquity
42 then I will remember My covenant with Jacob, and I will remember also My covenant with Isaac, and My covenant with Abraham as well, and I will remember the land.
What does God say about the heart condition of the disobedient Israelites?
What needs to happen to their hearts?
What happens then?
And when they do that, what will God remember?
How might these verses relate to the situation of the Galatians that Paul is dealing with?