G-d will establish you as His holy people, as He swore to you, if you safeguard the commandments of G-d, your G-d, and walk in His ways.
Following the path of Torah enables the soul to "walk."
Before the soul descends into the body, it experiences G-dliness in a relatively static fashion. Although it can experience some notion of elevation and movement, any new level reached can always be understood in the context of its previous level of spiritual understanding. This is a limited, step-by-step progress.
In contrast, once the soul has entered the body and is able to study the Torah and perform the commandments, it is able to move towards G-d with quantum leaps. This ability enables the individual to "walk," to truly progress in his relationship with G-d.