Strong’s Greek
G3155 — maten
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
μάτην
maten — pronounced mat'-ane
accusative case of a derivative of the base of 3145 (through the idea of tentative manipulation, i.e. unsuccessful search, or else of punishment); folly, i.e. (adverbially) to no purpose:--in vain. see GREEK for 3145
2 occurrences in the KJV.
Matthew 15:9
But in vain they do worship me, teaching for doctrines the commandments of men.
Mark 7:7
Howbeit in vain do they worship me, teaching for doctrines the commandments of men.