("Faith" is a very vast topic. Here is a short summary of what Faith is)
"The Law cannot save us" God gave the Ten Commandments in the past but it did not promise salvation, it promised only blessings. The Gospel of Jesus Christ alone can give salvation.
Clearly no one who relies on the law is justified before God, because
“the righteous will live by faith.” (Galatians 3:11, NIV)
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, NIV)
"We attain salvation by faith" We are saved by believing in the Jesus Christ, the Son of God. One has to believe in the death and resurrection of Jesus Christ, and by having faith in Jesus, he is saved from eternal damnation in Hell.
For God so loved the world that he gave his one and only Son, that
whoever believes in him shall not perish but have eternal life. (John
"We are saved by faith, not by works" Our good deeds cannot save us. Following the Commandments alone cannot save us. Whatever we do, whether for men or for God cannot save us. It is by faith alone that we are saved, and not by works.
For it is by grace you have been saved, through faith—and this is not
from yourselves, it is the gift of God— not by works, so that no one
can boast. (Ephesians 2:8-10, NIV)
"We need to live by faith" We need faith in our every day life. We need to walk by faith, we need to live by faith, we need to pray by faith and we need to worship God by faith. Without faith we cannot please God.
For we live by faith, not by sight. (2 Corinthians 5:7, NIV)
"Show your faith by your works" We need to show our faith by our action. We need to prove to others that we have faith, and that can be done only by works. For faith without work is dead, it is an incomplete faith and in fact, it is not faith at all.
But someone will say, “You have faith and I have works.” Show me your
faith apart from your works, and I will show you my faith by my works.
(James 2:18, ESV)
Hebrews 11 gives us a list of people who lived their life by faith.
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.
By faith Abel brought God a better offering than Cain did. By faith
he was commended as righteous, when God spoke well of his offerings.
And by faith Abel still speaks, even though he is dead.
By faith Enoch was taken from this life, so that he did not
experience death: “He could not be found, because God had taken him
away.” For before he was taken, he was commended as one who pleased
And without faith it is impossible to please God, because
anyone who comes to him must believe that he exists and that he
rewards those who earnestly seek him.
By faith Noah, when warned about things not yet seen, in holy fear
built an ark to save his family. By his faith he condemned the world
and became heir of the righteousness that is in keeping with faith.
By faith Abraham, when called to go to a place he would later
receive as his inheritance, obeyed and went, even though he did not
know where he was going.
(And the list goes on)