Heb 11:1  Now faith is the substance of things hoped for, the evidence of things not seen. 

Faith is quite often likened to a mustard seed.

Mat 17:19  Then the disciples came to Jesus apart, and said, Why could we not cast him out?
Mat 17:20  And Jesus said to them, Because of your unbelief. For truly I say to you, If you have faith like a grain of mustard seed, you shall say to this mountain, Move from here to there. And it shall move. And nothing shall be impossible to you. .

Notice lack of faith is associated with lack of belief. It is a requirement of God that we believe him, there is no faith without belief.

Luk 17:6  And the Lord said, If you had faith as a grain of mustard seed, you might say to this sycamine tree, Be rooted up and be planted in the sea! And it would obey you. 

If we just take those two verses then it is quite obvious that no one has any faith whatsoever, have you ever seen anyone move a mountain.
Some more about faith is learned from the following verse

Luke 17 v 3. And the apostles said unto the Lord increase our faith.

Why did the apostles want their faith increased if they could have moved mountains? They had faith but wanted it increased. This shows that they did not have enough faith. Notice the answer from Jesus.

Luk 17:6  And the Lord said, If you had faith as a grain of mustard seed, you might say to this sycamine tree, Be rooted up and be planted in the sea! And it would obey you. 

Notice that faith is likened to a mustard seed, which starts extremely small and grows extremely large.

Mat 13:31  He put out another parable to them, saying, The kingdom of Heaven is like a grain of mustard seed, which a man took and sowed in his field;
Mat 13:32  which indeed is the least of all seeds, but when it is grown it is the greatest among herbs and becomes a tree, so that the birds of the air come and lodge in its branches. 

It is obvious that people do not have enough faith to move mountains. We have to have our faith increased by God. By associating our faith to a mustard seed it is extremely plain that if we have a minute amount of faith we will eventually have great faith as we grow in grace and knowledge. Our faith is dependent on believing the Bible

Some characteristics associated with faith are as follows

Being afraid.  [the fearful will not be in Gods Kingdom Rev. 21 v 8]

Mat 8:26  And He said to them, Why are you afraid, little-faiths? Then He arose and rebuked the winds and the sea; and there was a great calm. 

Doubt.

Mat 14:31  And immediately Jesus stretched out His hand and caught him; and said to him, Little-faith! Why did you doubt? 

Lack of understanding.

Mat 16:8  And knowing Jesus said to them, Why do you reason among yourselves because you took no loaves, little-faiths?
Mat 16:9  Do you not yet understand, nor remember the five loaves of the five thousand, and how many hand baskets you took up; 

Faith can be increased.

Luk 17:5  And the apostles said to the Lord, Give us more faith. 

The just shall live by faith.

Rom 1:17  For in it the righteousness of God is revealed from faith to faith, as it is written, "The just shall live by faith." 

Faith comes from hearing the word of God.

Rom 10:17  Then faith is of hearing, and hearing by the Word of God. 

Faith cannot be feigned.

1Ti 1:5  But the end of the commandment is love out of a pure heart, and a good conscience, and faith unfeigned, 

We must not waver in our faith.

Jas 1:6  But let him ask in faith, doubting nothing. For he who doubts is like a wave of the sea, driven by the wind and tossed. 

Faith without works is dead

Jas 2:18  But someone will say, You have faith, and I have works. Show me your faith without your works, and I will show you my faith from my works. 

Jas 2:26  For as the body without the spirit is dead, so faith without works is dead also. 

Our faith will be tested

1Pe 1:7  so that the trial of your faith (being much more precious than that of gold that perishes, but being proven through fire) might be found to praise and honor and glory at the revelation of Jesus Christ,
1Pe 1:8  whom having not seen, you love; in whom not yet seeing, but believing in Him you exult with unspeakable joy, and having been glorified, 

The culmination of our faith is eternal life

1Pe 1:9  obtaining the end of your faith, the salvation of your souls.

We cannot please God without faith

Heb 11:6  But without faith it is impossible to please Him, for he who comes to God must believe that He is and that He is a rewarder of those who diligently seek Him. 

COMMENT. It is extremely obvious that faith the size of a mustard seed cannot move mountains, as we have to grow in faith. Rather, faith starts out small and then grows, just as a mustard seed does. We have the promise from God that our faith will grow if we keep all of Gods requirements as mentioned above, also faith is one of the fruits of the spirit, and as we grow in the spirit so our faith will grow.  Be assured that our faith will be tested which is far more precious than riches, so that it will be found at the return of Christ.