Ha, cousin Silence, that thou hadst seen that that
this knight and I have seen!—Ha, Sir John, said
We have heard the chimes at midnight, Master
That we have, that we have, that we have. In
faith, Sir John, we have. Our watchword was 'Hem,
boys.' Come, let's to dinner, come, let's to dinner.
Jesus, the days that we have seen! Come, come. (3.2.218-226)
As Silence and Shallow enthusiastically recall the heady days of their youth, Falstaff agrees that, yes, they have "heard the chimes at midnight." Falstaff's words are poignant but he's also somewhat dismissive of these two men. Later, he complains that old men are the biggest "liars." He says "This / same starved justice hath done nothing to prate to / me of the wildness of his youth, and the feats he / hath done about Turnbull Street: and every third / word a lie" (3.2.293-296). Falstaff points out that old men often misremember the past and inject the days of their youth with a glory that wasn't actually there.
Brain snack: Falstaff's famous line lends itself to the title of Orson Welles's study of Falstaff's character, Chimes at Midnight, You can watch Welles's film adaptation of this scene on YouTube.