As well as the primary source, context please.
The website of the Eisenhower Presidential Center attributes the quote to Ike at a 1953 press conference. A quick search hasn't yet turned up a transcript.
This quote has also been attributed to Ike:
All of us have heard this term 'preventative war' since the earliest days of Hitler. I recall that is about the first time I heard it. In this day and time... I don't believe there is such a thing; and, frankly, I wouldn't even listen to anyone seriously that came in and talked about such a thing.