This Bible contradiction is from the Skeptic's Annotated Bible.
Yes, you should pray for everyone.
1 Timothy 2:1 View context
I exhort therefore, that, first of all, supplications, prayers, intercessions, [and] giving of thanks, be made for all men;
No, there are some people you shouldn't pray for.
Jeremiah 7:16 View context
Therefore pray not thou for this people, neither lift up cry nor prayer for them, neither make intercession to me: for I will not hear thee.
Jeremiah 11:14 View context
Therefore pray not thou for this people, neither lift up a cry or prayer for them: for I will not hear [them] in the time that they cry unto me for their trouble.