Faith is one of those "outside the rectangle" things.
It's about what you can't see but you know is real, because eg. you've
grown up with it and saw in your family or Synagogue or church that God was there,
or seen God answer prayer,
heard about miracles,
read in the Bible and knew that it was true,
had angelic visitations or God dreams
or knew in your heart that Jesus/Yeshua could save you.
I became a Christian in 1982 after I heard a voice during a thunderstorm say to me I should buy a Bible and start reading it.
This is what I did. After I finsihed reading it all the way through I met someone who explained to me that you had to turn away from doing things your
own way and turn towards God's way. He said that Jesus gave his life to make me right with God and that I needed to receive God's
Spirit in my heart. I asked for this in prayer and my life was changed drastically, much for the better. I have seen many miracles happen since that.
More recently I have also started worshipping at a Synagogue, which has added a lot of extra depth and riches to my faith. Christianity in its pure
form is in fact a form of Judaism and Yeshua was a Jewish Rabbi who upheld the teachings of the Tenach/Old Testament.
Faith is for me one of the greatest treasures in my life, knowing that God is always there to make my life happen according to his plan and
that nothing can happen that is outside his control.
A lot of people don't have faith because they only dare to believe in the ordinary - the things that can be seen or proven academically.
That feels nice and safe, but it's a deception. Trying to believe by first working it out is going about it the wrong way round.
I've seen a lot of people trying this approach and they got nowhere.
I wrote a parable about this in my stories section.
The Bible says faith starts with something that happens in your heart.
It tells us to love God with all your heart, soul and strength (Deuteronomy/Dvarim 6:5) and that if we believe in our hearts we will be saved (Romans 10:9).
There are many things you can't see, such as eg nuclear radiation, that can be downright dangerous if you don't believe in them.
On the other hand blind faith (ie believing anything) can be just as bad.
Faith in God is something that will prove itself in the long haul, because God is faithful.