You can build an expression tree which contains an equality comparison using Expression.Equal method. For example, you have the following code.
bool value = 31 == 31;
Console.WriteLine(value);
Here is the code that is required to build the same functionality using expression tree.
Expression greaterThanExpr = Expression.Equal(
Expression.Constant(31),
Expression.Constant(31)
);
Console.WriteLine(Expression.Lambda<Func<bool>>(greaterThanExpr).Compile()());