Okay, this is my final Riley Riddle (and not my previous one), because I could not resist...
...and that meant this had to be even better.
Riddle me this:
My prefix will pray with an S,
My suffix is red with an A,
My infix, so ill with an F,
If only affixed with an E.
Because the answer is SAFE.
The answer is not "safe / SAFE". This is genuinely true; no wordplay involved.