Pesachim 118 - Cups three and four
The third and fourth cups of wine complete the Seder. He uses the third one to enhance the blessing after the meal, and the fourth - to finish praises. If he wants to drink more wine - it is OK in the beginning of the meal, but between the third and the fourth cups he should not drink, lest he become inebriated (since he is not eating any longer), and not complete the praises.
Multiple lessons are derived from those praises, and they are based on the proximity of the verses to one another. For example, since it says, "Praise the One who gives sustenance to every creature," and immediately after - "One who split the Red Sea," we conclude that man's sustenance is as hard as splitting the Red Sea.
Art: Pharaoh's Army Engulfed By The Red Sea by Frederick Arthur Bridgman