In real life I have never seen a mustard seed. But I have searched on Google for pictures of a mustard seed and its a very small seed. Why Would Jesus compare faith that could move a mountain to a mustard seed? Its so tiny. What He is saying is that it doesn't require a lot of faith, but it does require some faith. Faith is defined as "complete trust or confidence in someone or something:" and "strong belief in God or in the doctrines of a religion, based on spiritual apprehension rather than proof."
Hebrews 11: 6 - But without faith it is impossible to please Him: for he that cometh to God must believe that He is, and that he is a rewarder of them that diligently seek him.
Without any, zero, nada, zilch, no faith you cannot please God. You must believe He is God. In fact the verse states that God rewards those who diligently seek Him. The dictionary defines the word diligently as the following "in a way that shows care and conscientiousness in one's work or duties:" And just because I was curious, the word conscientiousness is defined as "(of a person) wishing to do what is right, especially to do one's work or duty well and thoroughly."
Matthew 18:3-4 - And said, Verily I say unto you, Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven. Whosoever therefore shall humble himself as this little child, the same is greatest in the kingdom of heaven.
I want to tell you today that if you believe in Jesus and He is your Lord and Savior, you do have faith. You don't need a lot to accomplish great things on His behalf. Its not you who is doing anything but trusting in God. So what is child like faith? When you tell a child, for example, "Don't touch the hot oven or you will get burned." they trust and believe you that you are not telling them this to harm them. But they believe and trust that you have their best interests for them. In that same way, have faith in what God says in the entire Bible. All the promises of God are yes and amen through Jesus Christ. Do you believe that? Rebuke the devil in the name of Jesus and tell him that you have a mustard seed and you are not afraid to use it!
2 Corinthians 5:7 - For we walk by faith, not by sight:
Easier said than done but all things are possible through Jesus. When we pray, we must have faith that God will answer. We may not see it yet but God will answer. We must trust in His timing, His wisdom, His judgement and in His power. Know that He is God. He sees and knows everything. God is everywhere! He knows each and everyone of us personally, better than our own selves. If the God who created everything in the heavens, in the sea and on the earth, what makes you think He cant handle your problems? We act like King Saul was with David. He wanted David to sing the evil spirits away and fight his battles. But Saul didn't want David to be king. Let Jesus rule your entire life. He can do so much more with your life than you ever could.