Menger's theorem and how many pairwise-edge disjoint paths?

Question

In a proof, I came across this statement:

 By Menger's Theorem, for each $x,y$ there are $k'(G)$ 
 pairwise edge-disjoint $x,y$ path, where $k'(G)$ is the minimum size 
 of a disconnecting set of edges.

Why is this true? It was not proven, but stated like it was supposed to be obvious. (It's not to me.)

Answer 1

This is not an obvious theorem, but it is quite well known. Here is a one proof.