Build a tower (purgon oikodomhsai). A common metaphor, either a tower in the city wall like that by the Pool of Siloam ( Luke 13:4 ) or a watchtower in a vineyard ( Matthew 21:33 ) or a tower-shaped building for refuge or ornament as here. This parable of the rash builder has the lesson of counting the cost. Sit down (kaqisa). Attitude of deliberation. First (prwton). First things first. So in verse Matthew 31 . Count (pshpizei). Common verb in late writers, but only here and Revelation 13:18 in the N.T. The verb is from pshpo, a stone, which was used in voting and so counting. Calculate is from the Latin calculus, a pebble. To vote was to cast a pebble (tiqhmi pshpon). Luke has Paul using "deposit a pebble" for casting his vote ( Acts 26:10 ). The cost (thn dapanhn). Old and common word, but here only in the N.T. from daptw, to tear, consume, devour. Expense is something which eats up one's resources. Whether he hath wherewith to complete it (ei ecei ei apartismon). If he has anything for completion of it. Apartismon is a rare and late word (in the papyri and only here in the N.T.). It is from apartizw, to finish off (ap- and artizw like our articulate), to make even or square. Cf. exhrtismeno in 2 Timothy 3:17 .