The two triads "mens, notitia, amor" (trin. 9) and "memoria, intellegentia, voluntas" (trin. 10) are keys to understanding Augustine's Trinitarian triads in De Trinitate. However, Augustine's intention in proceeding from "mens, notitia, amor" to "memoria, intellegentia, voluntas" remains unclear. There is a common tendency to regard the latter triad as superior to the former one because the latter one displays a more dynamic dimension through the actions: remembering, understanding, willing. This dynamic perspective, however, cannot give a full account of the complicated relationship between the two triads displayed in trin. 11-15. This paper proposes a complementary relationship in viewing the two triads in trin. 9-10. Through investigating Augustine's attitudes towards knowledge and love in the two triads, it aims to reveal that the two triads, while similar in content, can provide different dimensions in understanding the relationship between knowledge and love. In proceeding from one triad to another, Augustine is pondering how knowledge and love can be related to each other, which, in turn, also represents the relationship between the Son and the Holy Spirit within the Trinity. Such an approach in viewing the two triads will lead us to see that Augustine regards the triads as tools for Christian contemplation and that the investigation of the Trinity is a spiritual exercise. It can also explain why, alongside the philosophical modes of discussion, Augustine brings in many Christian elements like fides(trin. 13) and imago dei (trin. 14-15).