From Rabbi Avraham ben HaRambam (Maimonides), Sefer HaMaspik (“The Guide to Serving God”), translated by Rabbi Yaakov Wincelberg (Feldheim Books), p. 495. Although footnotes have been omitted, we have added explanatory information in parentheses.
OUTWARD AND INWARD RETREAT
The Prophets and their disciples, the chasidim (devout), practiced outward retreat, which led to inward retreat. To practice outward retreat, one must isolate himself from other people, avoid their gatherings, and separate from them. This is in order to be free from what entangles them and free from the distractions caused by seeing them, hearing their conversations, and being involved in their affairs. As a result, one will be able to achieve a glimpse of the majesty of the Creator. One will be able to delight in His angels and the splendor of His creatures, by meditating upon them and contemplating their closeness to God and their loftiness." Of this, David said, "How precious to me are Your friends, how great is their number! If I would attempt to count them, I would find them to be more numerous than the grains of sand" (Tehillim 139:17-18). He was so absorbed in this meditation that he entered a state of prophetic slumber or stillness and achieved a degree of Encounter with God. Even when he awakened, he retained the effects of that Encounter, as he said, "I awoke and remained with You."
Outward retreat might be total, such as to separate from the city to isolate oneself in deserts, mountains, or other uninhabited places. It might be partial, such as to isolate oneself in houses. It might be frequent, or occasional; for long periods, or for short periods. But it is impossible in this world for one to retreat for an entire lifetime.