The centurion in Matthew 8 demonstrates faith.
Matthew 8:5 Now when Jesus had entered Capernaum, a centurion came to Him, pleading with Him, 6; saying, "Lord, my servant is lying at home paralyzed, dreadfully tormented." 7 And Jesus said to him, "I will come and heal him." 8 The centurion answered and said, "Lord, I am not worthy that You should come under my roof. But only speak a word, and my servant will be healed. 9 "For I also am a man under authority, having soldiers under me. And I say to this one, ‘Go,’ and he goes; and to another, ‘Come,’ and he comes; and to my servant, ‘Do this,’ and he does it." 10 When Jesus heard it, He marveled, and said to those who followed, "Assuredly, I say to you, I have not found such great faith, not even in Israel! 11 "And I say to you that many will come from east and west, and sit down with Abraham, Isaac, and Jacob in the kingdom of heaven. 12 "But the sons of the kingdom will be cast out into outer darkness. There will be weeping and gnashing of teeth." 13 Then Jesus said to the centurion, "Go your way; and as you have believed, so let it be done for you." And his servant was healed that same hour.
The centurion believed that Jesus could heal with a word without needing to see or lay hands on his servant. He was so convinced of this that he stopped Jesus travelling to his house.
Here's a definition of faith from Strong’s Concordance:
Faith <4102> πίστις pistis; from <3982> πείθω peitho (persuade, trust, have confidence). Translated in the King James Version – ‘faith’ 239 times, ‘assurance’ 1 time, ‘believe + 1537’ 1 time, ‘belief’ 1 time, ‘them that believe’ 1 time, ‘fidelity’ 1 time. Meaning: Credence; moral conviction (of religious truth, or the truthfulness of God or a religious teacher), especially reliance upon Christ for salvation; abstractly, constancy in such profession; by extension, the system of religious (Gospel) truth itself.
Faith is more than just belief. We can believe something without doing anything about it. Faith is a combination of belief and action. You cannot have one without the other. It is what we do to demonstrate our belief.
The writer to the Hebrews describes it thus:
Hebrews 11:1 Now faith is the substance of things hoped for, the evidence of things not seen.
Hebrews 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.
James 2:14 What does it profit, my brethren, if someone says he has faith but does not have works? Can faith save him? 15 If a brother or sister is naked and destitute of daily food, 16 and one of you says to them, "Depart in peace, be warmed and filled," but you do not give them the things which are needed for the body, what does it profit? 17 Thus also faith by itself, if it does not have works, is dead. 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 by my works. 19 You believe that there is one God. You do well. Even the demons believe—and tremble! 20 But do you want to know, O foolish man, that faith without works is dead? 21 Was not Abraham our father justified by works when he offered Isaac his son on the altar? 22 Do you see that faith was working together with his works, and by works faith was made perfect? 23 And the Scripture was fulfilled which says, "Abraham believed God, and it was accounted to him for righteousness." And he was called the friend of God.
We might conclude that faith has substance in what we do because of what we believe; that faith is belief in action.
I hope you find this helpful.