"I knew one thing: as soon as anyone said you didn't need a gun, you'd better take one along that worked"

This quote by Raymond Chandler is a warning to be prepared for any kind of situation. It suggests that even if somebody tells you that you do not require a weapon, it is still important to have one with you that is in working problem. This can be interpreted as an allegory for being prepared for any kind of circumstance in life. It is essential to be planned for the unforeseen as well as to have the necessary devices to take care of any type of scenario. This quote is a pointer to constantly be prepared as well as to have the right devices for the work. It is also a suggestion to not listen at face value as well as to always be prepared for the most awful.