You can reduce the $MP= \{\langle M,w \rangle : w \in L(M)\}$ to $NeverHalt$ For a given string $\langle M,w \rangle $ you construct the following machine $F$: For input x: Simulate M for input w if it accepts, loop if it rejects accept x Now you can see that $\langle M,w \rangle \in MP \iff \langle F \rangle \in NeverHalt$