Ek (ἐκ, used before consonants) / ex (ἐξ, used before vowels) is one of the most common Greek prepositions, occurring over 900 times in the NT. It always takes the genitive case and fundamentally expresses origin, source, or separation: "out of," "from," or "by means of." It answers the question: where did this come from?
Its opposite is eis (G1519, into). Together they map movement: things come ek (out of) one sphere and go eis (into) another. In theological usage this is crucial for understanding incarnation, salvation, and eschatology.
Ek carries enormous theological freight. The Word came "from" (ek) the Father (John 8:42). Christians are "born from" (ek) God (John 1:13; 1 John 3:9). Salvation is "from" (ek) faith (Romans 1:17, ek pisteōs eis pistin — from faith to faith). The church is called "out of" (ek) the world (John 17:15-16; ekklēsia, "called out ones," is built from ek + kaleō).
The resurrection is described as "from" (ek) the dead — Jesus came out from among the dead ones, blazing a path for all who belong to him. Every believer's identity is defined by this ek: called out of darkness, born from above, citizens from heaven (Phil. 3:20). The preposition of origin defines destiny.