We know how easily affected we are by our environment -- our skin tans with sunlight, our taste buds activate when we see food, and so on. Our sense of self, too, is highly susceptible to environmental cues (both external and internal environments). In essence, what we experience as our self and, by extension, self-esteem, is a powerful depiction generated by our brain.
Whenever I come across a new book or material about spirituality, I feel that I'm in touch with something bigger than me because of the author's profound knowledge, dedication, and experience. Over the years, they've become my spiritual family by sharing their insights on love and compassion, and the power of prayer and meditation.