A.T. Robertson Commentary Luke 20:44

"David therefore calleth him Lord, and how is he his son?" — Luke 20:44 (ASV)

David therefore (Δαυειδ ουν). Without ε as in Mt 22:45. On the basis of this definite piece of exegesis (ουν, therefore) Jesus presses the problem (πως, how) for an explanation. The deity and the humanity of the Messiah in Ps 110 are thus set forth, the very problems that disturbed the rabbis then and that upset many critics today.