Religion not required
Within this website I explore whether there is a spiritual realm, a supernatural realm, containing God, mind, souls, consciousness with its contents (ideas, emotions, love, reason, etc) — this, from a purely philosophical and unreligious point of view. I first assume there is a spiritual realm so as to explore the implications; then I present my conclusions (in this article and related articles).
Christians claim there is no basis for morality apart from Christianity and the Bible. This is false for these reasons:
Other religions have similar claims about the basis for morality; why should we prefer Christian claims?
Where does the concept of goodness come from with its superiority to evil? Perhaps it's merely a result of our capacity to suffer; to experience physical bodily pain, and psychological and emotional anguish?
And also, our built-in desire to be happy. And to experience awe in the presence of great art or music or scenery (for example).
But for that matter, where do any of our ideas, concepts, and feelings come from? "Why" questions such as these can never be answered; they are beyond our capability to know.
Suffering of conscious creatures exists. Conscious suffering is the only evil. Without suffering there is no evil.
Suffering exists because of: (1) physical pain enabled by having sense organs of pain, and (2) psychological anguish and misery generated by the brain itself.
I would guess that: Those we call evil who inflict suffering (physical and psychological) on others also themselves suffer in performing these evil deeds (but there are probably rare exceptions). Psychological disorders cause distress to the afflicted.
What is the source of the sensation of suffering? It's unknown, the same as the source of consciousness itself is unknown. Certainly a good God didn't create: (1) suffering, nor (2) the senses generating pain, nor (3) the brain structures triggering the sensation of physical pain and psychological distress.
The problem of evil is not solved by invoking: (1) God, or (2) a spiritual realm having spirits and souls. It's unknown, perhaps unknowable, why suffering exists.
Certainly Christianity, with its evil God who created evil and inflicts suffering; this doesn't explain evil.