Myth: Whatever we believe that is true to us, if you do not believe that is your own interest, but it is true to me, because I believe it.
Faith: Faith is actually based on substantial truth, not just because we believe in it.
Faith is actually believing the unseen as it is mentioned in the bible in Hebrews 11:1
According to this verse faith is the proof of fact that things which are hoping for exist actually and we are waiting for them to be revealed.
If we observe every human being, belonging to whichever religion (except athiests) believes God is there, He hears us, He will oversee our lives, He will keep us safe, protect us etc etc.
If we consider a doctor treating a critically ill person, untill when the body is responding to the treatment, though there are minimal signs of improvement, the doctor keeps working, and when the body stops responding he says "no faith". In this case, the ground of faith can be understood as the all the processes in the patients body that work towards healing. That means they are what the word "faith" of the doctor are based upon. Just as functioning of these complex processes forms the basis of "faith" in case of a patient, faith in God must also be based on something substantial and real. But understanding God maybe a highly specialised task just like a specialist doctor understand the patients response.
It is just like the "theorem and the converse" If the theorem is that 'radius of a circle is the distance between the centre to any point on periphery', the converse is 'if you draw a shape connecting all points with equal distance from the centre it becomes a circle'. Likewise if 'faith in God' is the theorem, then 'existence of God himself' is the converse.
So God is a pre-existent being, not created after the human race came into existence. Therefore it always wise to rever God for what He is actually, but not for what He is for us/what He did for us. If we are trying to give him to a particular form, that means we are trying limit him into a form, where true nature of God is infinity, No Begining and No End. That is why it is important to develop faith in God himself and worship him truely instead of anything else or anyone else, and God shall reveal himself in due time for those who seek him, from any sort of faith/religion.
Man believes there is God, but not able to appreciate the true God. Thus many came in the name of God, some true and some false, some misleading, but the purpose of human life is to connect with the God who actually is the author for the soul he is carrying. Just as a lay man cannot understand the pathophysiological condition in a patient except the specialist, a human being cannot appreciate the truth of God, without special introduction.