Behold, he whose soul is not upright in him shall fail, but the righteous shall live by his faith. (Habakkuk 2:4 - ASV)

What does it mean to have "faith" from an Hebraic perspective? In our western minds faith is a mental exercise in knowing that someone or something exists or will act. For instance, if we say "I have faith in God" we are saying "I know that God exists and that he will do what he says he will do".

The Hebrew word for faith is אמונה (emunah - Strong's #530) and is an action oriented word meaning "support". This is important because the Western concept of faith places the action on the one you have faith in, such as "faith in God". But, the Hebrew word אמונה places the action on the one who "supports God". It is not a knowing that God will act, but rather I will do what I can to support God. This idea of support for the word emunah can be seen in Exodus 17:12.

But Moses' hands grew weary; so they took a stone and put it under him, and he sat upon it, and Aaron and Hur held up his hands, one on one side, and the other on the other side; so his hands were steady (emunah)until the going down of the sun.

It is the support/emunah of Aaron and Hur that held of Moses' arms, not the support/emunah of Moses. When we say "I have faith in God", we should be thinking "I will do what I can to support God".