From alpha 1143.
The quotation is Aristophanes, Clouds 815; Strepsiades, recently returned from Socrates' Think-Tank, says this to his son (web address 1). A scholion to the line explains it thus: "i.e. having gone over to the house of your maternal uncle, Megakles, eat up the columns of that house, which are the only things remaining now that you have devoured everything else" (a)ll' ei)selqw\n ei)s th\n au)lh\n tou= pro\s mhtro/s soi qei/ou *megakle/ous kate/sqie tou\s ki/onas au)th=s, ou(\s e)kei=nos mo/nous katale/loipe katabebrwkw\s a(/panta ta)/lla.) So Strepsiades is accusing Pheidippides of having squandered the family's fortune; the only things left are the very pillars or columns of his uncle's house.
NB: the ancient scholiasts and modern commentators alike miss the joke inherent in the phrase itself: Megakles' pillars rather than the familiar pillars, stelai, of Herakles (eta 464, and cf. under gamma 29, chi 136).