Quote:
{4:94} O you who have believed, when you go forth [to fight] in the cause of God, investigate; and do not say to one who gives you [a greeting of] peace "You are not a believer," aspiring for the goods of worldly life; for with God are many acquisitions. You [yourselves] were like that before; then God conferred His favor upon you, so investigate. Indeed God is ever, with what you do, Acquainted.
I can see why the translator thought of "investigate" as a translation of
تبينوا. Pickthall offered a closer translation with "discriminate" and Asad did too when he translated it "use your discernment." The verb means to make the effort to separate from the mix. The preposition
بين (between) is derived from it.
I suggest,
{4:94} O you who have believed, when you have stricken (ventured out) in the cause of God, then differentiate; and do not say to one who cast to you [a greeting of] peace "You are not a believer," desiring the ephemeral of [this] the nearest life; for with God are many acquisitions. You were like that before, then God conferred favor upon you. So, differentiate. Verily, God has ever been, of what you do, All-Aware.