From the Summa Theologiae of Thomas Aquinas, First Part, Question 2. Quia igitur principalis intentio huius sacrae doctrinae est Dei cognitionem tradere, et non solum secundum quod in se est, sed etiam secundum quod est principium rerum et finis earum, et specialiter rationalis creaturae, ut ex dictis est manifestum; ad huius doctrinae expositionem intendentes, primo tractabimus de Deo; secundo, de motu rationalis creaturae in Deum; tertio, de Christo, qui, secundum quod homo, via est nobis tendendi in Deum. Therefore, because the principal intent of this sacred doctrine is to teach the knowledge of God, and not only according as He exists in Himself, but also according as He is the beginning of things and their end, and especially of rational creatures, as is manifest from what has been already said, ........... exposition of this doctrine ................ , first, we shall treat of God; second, of the rational creature's motion towards God; third, of Christ, who, according as he is man, is our way to be stretched out to God. What is the meaning of the bold-faced phrase? expositionem huius doctrinae = exposition of this doctrine But, how does the preposition ad and the partciple intendentes affect the translation?