[Peyton pours some of the wine into the second glass]
LORELAI: Aw. You’re the Solomon of wine.
Lorelai refers to King Solomon, a monarch in the Hebrew Bible and Old Testament renowned for his wisdom, to the point that calling someone “a Solomon” means that they are very wise.
The best known story about him is The Judgement of Solomon, in which two prostitutes who lived together gave birth the same day. Only one of the babies lived, and both women laid claim to being its mother. Solomon easily resolved the dispute by commanding the child to be cut in half and shared between the two. One woman promptly renounced her claim, proving that she would rather give the child up than see it killed. Solomon declared the woman who showed compassion to be the true mother, entitled to the whole child.
Lorelai means that Peyton is like Solomon because he resolves his playful “dispute” with Lorelai over the last glass of wine by pouring it into two glasses (cutting the wine in two).
[Painting is The Judgement of Solomon by Nicolas Poussin, 1649]