In the Jewish tradition these two psalms belong together. And are read together when you don't feel safe: because of depression, illness, or tormenting thoughts or entites.
Psalm 90 corresponds to the Hebrew letter Tsade (צ), that relates to the Righteous Man (Tzadik) invoking the spiritual merits of the Righteous.
Its combination of words and letters connect to the Holy Name Shaddai (שד״י), famously associated with boundaries and protection.
Psalm 91 is a potent evil-warding text. The spiritual meaning of its number refers to divine union and angelic protection.
It is designated as an anti-demonic song used to ward off night terrors, pestilence, hostile spirits, bad thought or emotion, and any destructive entities.
The ancient mystical traditions view them as a powerful prayer for healing and protection, granting divine refuge, and overcoming emotional or spiritual heaviness.
Psalms are Jewish. Miraculous power were assigned to them. Later, Christians adopted them. To activate their magic we should better stick to the Jewish instruction.
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