Strong's G4599 — σθενόω (verb)
sthenoo (sthen-oh'-o) v.
1. to strengthen
2. (figuratively) to confirm (in spiritual knowledge and power)
[from sthenos "bodily vigor" (probably akin to the base of G2476)]
KJV: strengthen 
Compare: G1840, G2902 
See also: G2476 
Occurrences: 1