In Genesis 3:1, we see the first question asked in the Bible. sadly, it is Satan who asks it, and it is for the expressed purpose of raising doubt concerning the Word of God.
Some would suggest that this is a good example why we should never question God's Word; however, it is important to remember Satan's purpose in the question. Satan sought to drive a wedge between God and man. Questioning God's Word is never a bad thing when it helps us to better understand what God has said so that we may draw closer to Him, but they should never be used to deter our faith or lead us to doubt His goodness and faithfulness.