Allah, the Exalted says, "Do you not see how Allah sets forth a metaphor of a good word: a good tree whose roots are firm and whose branches are in the sky? It bears fruit all the time by its Lord's permission. Allah sets forth metaphors for people so that they will pay heed." (Surat Ibraaheem, 14:24-25) Allah likens the statement of faith, which is the best of statements, with a tree that is the best of trees bearing these noble characteristics. Its roots are firm, it is always growing and maturing and it bears fruit all the time, directing is numerous benefits and delectable fruits to its owner and others. This tree varies greatly in the hearts of the believers, changing in accordance with the variation of the qualities that Allah has described it with. Therefore, it is upon the servant to hasten towards acquiring knowledge about it, its descriptions, that which leads to its existence and potency, its roots and its branches.He has to expend his efforts in actualizing this tree in terms of knowledge and action, for indeed his portion of goodness and success, happiness in this life and the hereafter, depends upon the extent to which this tree is implanted in the heart. (taken from the author's introduction)