Akavya ben Mehalel said: “Reflect upon three things and you will not come near sin: Know from where you came, and to where you are going, and before whom you are destined to give an accounting...” (Ethics 3:1)
Reflect upon three things - all three together. If you reflect on only one, or some of them, not only will they be ineffective, but such a meditation could even cause harm. If you reflect only on the first, you will come to the conclusion that you are not to blame for anything. If you reflect only on where you are going you might mistakenly believe that there is no ultimate judgment and accounting. Therefore, we are told to also reflect on “before Whom you are destined to give an accounting.” All three aspects of this mediation are dependent upon each other. (Midrash Shmuel)
This Mishna teaches a person that he must have three entities in mind and when he does so, he “will not come to sin.” Generally, a person thinks about two entities, himself and G-d, for “I was created solely to serve my Creator.” We must be aware of a third entity, the world at large. The world was created by G-d for a Jew to use in service of Him, i.e., that a Jew should refine his body and his soul, and spread refinement in the world at large, transforming it into a dwelling for G-d.
(The Lubavitcher Rebbe, 13 Iyar, 5751 1991)