Kabbalah sa Jeremias 17:7: Sha'arei Kedusha

In contrast, there is no greater quality than trust in HaShem-יהו״ה, blessed is He, as written,⁴⁶⁵Psalms 2:12 “Happy are all who trust in Him.” A person who has this quality is faithful that there is a God in the world, who is all-capable and supervises over everything. It thus is written,⁴⁶⁶Jeremiah 17:7 “Blessed is the man who trusts in HaShem-יהו״ה, HaShem-יהו״ה will be his security.” Such a person is certain that he will not lack sustenance, as written,⁴⁶⁷Psalms 55:23 “Cast your burden upon HaShem-יהו״ה and He will sustain you.” However, this applies on condition that his trust in HaShem-יהו״ה is truly sincere, with all his heart and without doubt. This is evident by the fact that if he truly trusts in HaShem-יהו״ה, blessed is He, he will occupy himself in studying His Torah and fulfilling His mitzvot with all his heart and without any misgivings.