Linq Ensure All Items of List A Are in List B

Question

I have a pretty straightforward question and want to solve it in the best way possible. I know this can be solved with a simple loop but I would prefer using linq.

// Yields true because B contains all of A
IEnumerable<int> listA = new int[] { 1, 2, 3, 4 };
IEnumerable<int> listB = new int[] { 1, 2, 3, 4, 5, 6 };

// Yields false because B does not contain all of A
IEnumerable<int> listA = new int[] { 1, 2, 3, 4 };
IEnumerable<int> listB = new int[] { 2, 3, 4, 5, 6 };