But I am sure the younger of our nature,That surfeit on their ease, will day by day
The Italian duke has complained that the old king of France hasn't joined their war. Here, the first lord Dumaine assures him that France's young noblemen will likely join his army. What's interesting is that the Lord talks about the younger men as if they're a bunch of bored school kids who don't get enough exercise. Of course, this also suggests that the Italian battlefield is like some kind of jungle gym.