We need simple faith to believe God's Word and His promise. We don't need a sign - remember faith comes by hearing the Word of God, not through signs. "What His mouth has spoken, His hands are also able to perform" - Bishop Oyedepo

http://bible.us/Mark8.11.NKJV

Then the Pharisees came out and began to dispute with Him, seeking from Him a sign from heaven, testing Him. But He sighed deeply in His spirit, and said, “Why does this generation seek a sign? Assuredly, I say to you, no sign shall be given to this generation.”