Strong’s Greek
G2901 — krataioo
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
κραταιόω
krataioo — pronounced krat-ah-yo'-o
from 2900; to empower, i.e. (passively) increase in vigor:--be strengthened, be (wax) strong. see GREEK for 2900
4 occurrences in the KJV.
Luke 1:80
And the child grew, and waxed strong in spirit, and was in the deserts till the day of his shewing unto Israel.
Luke 2:40
And the child grew, and waxed strong in spirit, filled with wisdom: and the grace of God was upon him.
1 Corinthians 16:13
Watch ye, stand fast in the faith, quit you like men, be strong.
Ephesians 3:16
That he would grant you, according to the riches of his glory, to be strengthened with might by his Spirit in the inner man;