He replied, “Because you have so little faith. Truly I tell you, 
if you have faith as small as a mustard seed, you can say to this 
mountain, ‘Move from here to there,’ and it will move. Nothing will 
be impossible for you.”

Matthew 17:20

“Have faith in God,” Jesus answered. “Truly I tell you, if anyone 
says to this mountain, ‘Go, throw yourself into the sea,’ and does 
not doubt in their heart but believes that what they say will happen,
it will be done for them. Therefore I tell you, whatever you ask for 
in prayer, believe that you have received it, and it will be yours. 
And when you stand praying, if you hold anything against anyone, 
forgive them, so that your Father in heaven may forgive you your sins.”

Mark 11:22-26

For in the gospel the righteousness of God is revealed—a righteousness
that is by faith from first to last, just as it is written: “The 
righteous will live by faith.”

Romans 1:17

"Therefore, since we have been justified through faith, we have peace
with God through our Lord Jesus Christ, through whom we have gained 
access by faith into this grace in which we now stand. And we boast 
in the hope of the glory of God."

Romans 5:1-2

But what does it say? “The word is near you; it is in your mouth and 
in your heart,” that is, the message concerning faith that we proclaim.
If you declare with your mouth, “Jesus is Lord,” and believe in your
heart that God raised him from the dead, you will be saved. For it is
with your heart that you believe and are justified, and it is with 
your mouth that you profess your faith and are saved. As Scripture 
says, “Anyone who believes in him will never be put to shame.”

Romans 10:8-11

"Now faith is confidence in what we hope for and assurance about what
we do not see. This is what the ancients were commended for. By faith
we understand that the universe was formed at God’s command, so that 
what is seen was not made out of what was visible."

Hebrews 11:1-3

"Fixing our eyes on Jesus, the pioneer and perfecter of faith. For 
the joy set before him he endured the cross, scorning its shame, and 
sat down at the right hand of the throne of God."

Hebrews 12:2

"In all this you greatly rejoice, though now for a little while you 
may have had to suffer grief in all kinds of trials. These have come 
so that the proven genuineness of your faith—of greater worth than 
gold, which perishes even though refined by fire—may result in praise,
glory and honor when Jesus Christ is revealed. Though you have not 
seen him, you love him; and even though you do not see him now, you 
believe in him and are filled with an inexpressible and glorious joy, 
for you are receiving the end result of your faith, the salvation of 
your souls."

1 Peter 1:6-9