The Maharal makes a GREAT point. Liberty alone is dangerous. People are bound to lose their bearings and act immorally and without restraint. So right after we were freed from Egypt we were bound to Hashem as His servants.
The third cup of wine on Pesach corresponds to the pasuk וגאלתי אתכם לי לעם - redemption, and the fourth ולקחתי אתכם לי לעם. We must go right from redemption to servitude to Hashem. So don't make a hefsek between the third and fourth cups!!
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