If God is beyond our comprehension how can we comprehend what he wants? According to many christian practitioners one of their most famous answers to a lot of questions in that "God is above our understanding" or another similar answer.  

If this is true then how can we comprehend what god wants from us? The bible is written by many people who aren't God, so how can we base anything off of mere mortals who cannot comprehend such a supreme being? 

PS Please no cryptic responses
If by "comprehension" you mean "completely understanding God," then, yes, God is not comprehensible. But if by "comprehension" you mean "knowing God," then, no. God's existence and divinity are knowable to unaided human reason and even demonstrable:


  Rom. 1:20: For the invisible things of him, from the creation of the world, are clearly seen, being understood by the things that are made; his eternal power also, and divinity: so that they [the unbelieving Romans] are inexcusable [for not knowing God].


We also know what God wants for us:


  1 Thess. 4:3: For this is the will of God, your sanctification