Dreams involving diabolical altars, spell books, and demonic voices can evoke strong feelings and may reflect your subconscious thoughts, fears, or concerns. Here are some interpretations of the symbols in your dream:

1. Diabolical Altar and Spell Book: These elements may symbolize a search for power or control in your life, perhaps relating to situations where you feel you need to take charge or influence outcomes. It could also indicate inner conflict regarding morality or ethical dilemmas.
2. Candles and Bay Leaves: Candles often represent illumination and guidance, while bay leaves can symbolize victory or protection. Together, they might suggest a desire for clarity in a confusing situation or a need to protect yourself from negative influences.
3. Holding a Phone with a Recorded Voice: The phone symbolizes communication, and the recorded voice may represent a message you are receiving from your subconscious. The deep, demonic voice saying something seemingly paradoxical ("His voice is like an angel from heaven") could indicate inner turmoil or conflict between good and evil, or perhaps a struggle with concepts of trust and betrayal.
4. Thought the Voice was Satan: This aspect of your dream might signify fears or anxieties about temptation, manipulation, or the darker sides of human nature. It could suggest that you are grappling with issues of trust in your life or feeling overwhelmed by negative influences.

Overall, this dream could be highlighting a conflict between your desires and the moral implications of those desires. It may be beneficial to reflect on any current situations in your life where you feel torn between opposing forces or where you seek clarity. Consider journaling your feelings or talking to someone you trust to gain further insight into what this dream might be revealing about your waking life.