Ya'akov Avinu's dream in which he envisions angels ascending and descending a ladder whose base is rooted on earth and whose apex reaches toward heaven has been interpreted in many different distinct but complementary fashions (see Rashi, Midrash Rabba, etc.). R. Meir Leibush Malbim presents an original interpretation which highlights the immense significance of human activity. Before Ya'akov's journey to Lavan's house, the time-period during which he would mold and solidify his patriarchal personality and emerge as the b'chir sheb'avot, the choicest of our patriarchs, he is shown the immense effects of his activities.
Every positive act of Divine service, every mitzva, generates not only merit and reward for its performer, but also creates spiritual forces in the world which serve as a vehicle of Divine protection and goodness for the individual, the entire Jewish community, and even the entire world. The Mishna Avot (4:13) underscores the same idea: "He who performs one mitzva, acquires for himself a defending angel; he who violates one aveira, acquires for himself one prosecuting angel." This concept was actively demonstrated to Ya'akov via the vision of the ladder. The ascending angels represented those angels created as a result of Ya'akov's uninterrupted Torah study for 14 years in Yeshivat Shem V'Eiver, his kibbud 'av v'aim, and his other myriad mitzvot. The descending angels represented these same created angels being sent down to the world to protect Ya'akov and increase Divine bounty in the world. The measure of Divine protection offered via these "guardian angels" is directly commensurate with the amount and quality of the mitzvot performed.
The Talmud ( Masechet B'rachot 60b) teaches a similar concept. There it is taught that before entering the bathroom, one should recite a short passage requesting that the two guardian angels accompanying the person should await his return. Shulchan Aruch(3:1) notes that it is no longer customary to recite this statement since we cannot be certain that we merit these guardian angels. Once again the interrelationship between the performance of mitzvot and angels of protection emerges.
While it is often stressed that mitzvot elevate the person's character, refine his soul, and lead to increased nearness to Hashem, this aspect of mitzvot -- as instruments causing the actual creation of angels leading to increased Divine protection -- is often overlooked. Knowledge and contemplation of this great power bestowed by Hashem on mankind whereby human beings are able to serve as a direct partner with Hashem in the creation of positive spiritual forces in the world leading to greater Divine goodness and bounty should serve as a strong impetus for us to increase our devotion to Avodat Hashem. (See Nefesh HaChayim ( Sha'ar 1) which further expands on the theme of the immense power with which Man, by virtue of his actions, is endowed.)