There seems to be a disconnect in how we're talking about this. You seem to be understanding the quote as a statement on preparedness; if you want peace, you should ensure your military is heavily funded and capable of repelling all comers.

My read was more about anticipation; if you want peace, you should plan for war.

On the surface it seems like we're saying the same thing, but it comes into conflict when we run into historical examples. Like to my mind, Rome was always preparing for war, at the time of the quote they were waging wars like clockwork. But it's that very habit of bullying their neighbors that put such a large target on their backs.

By contrast, Britain had been working towards disarmament for years before they shifted gears, there was a reason Chamberlain had to buy so much time. Germany on the other hand had been working tirelessly towards their goals of conquest. Germany had been preparing for war while Britain was preparing for peace.

Does that make sense from your perspective?