This here is the work of God that you might rely on whoever that Person [God] has sent.
Jhn 6:29 this is the work of God, that ye believe on him whom he hath sent.
Interesting and Hidden Aspects:
While this sounds as if all we must do is trust in the one sent by God, the Greek says something more.
Christ says this in response to being asked by the crowd what they might do to "work the work of God." This is the crowd's response to Christ's previous statement telling the crowd not to work for that which destroys, but to work for that which strengthens and leads to eternal life.
This verse starts with the Greek word Τοῦτό, which is a word accentuating the demonstrative pronoun ("this") by repeating it. In English, we might say "this here." This would seem to refer to the discussion that they are having. It is having the discussion, asking about what is right, that does the work of God.
What does this discussion accomplish? The word "hina," translated as "that" is a word that answers that question. Its more complete sense is "in order that." So the final part of this verse describes why this discussion is important: it creates trust in whoever God has sent.
The "subject" of the last phrase is ekeinos, a word that indicates a particular person, place, or method. Here, the word seems to refer to "God." Christ consistently refers to God as the one who sent him. The form here is a little different however. Usually, "the sender" is identified by a present participle, "the one sending."
This verse indicates that is purpose of the work to trust someone sent by God. However, he work involves asking questions and discussing ideas. Or, in our case, understanding Christ's words or trying to.
πιστεύητε 2nd pl pres subj act) "Ye .believe" is from pisteuô (pisteuo), which means "to trust, put faith in, or rely on a person", "to believe in someone's words", "to comply", "to feel confident in a thing," and "to entrust in a thing."
εἰς "On" is from eis (eis), which means "into (of place)," "up to (of time)", "until (of time)", "as much as (of measure or limit)", "as far as (of measure or limit)", "towards (to express relation)", "in regard to (to express relation)", "of an end or limit," and "for (of purpose or object)."
ὃν "Him" is from hos (hos), which is the demonstrative pronoun in its various forms (hê, ho, gen. hou, hês, hou, etc. ; dat. pl. hois, hais, hois, etc. gen. hoou). It means "this", "that", "he", "she", "which", "what", "who", "whosoever", "where", "for which reason," and many similar meanings.