This one sounds egocentric at the first look but is actually quite the opposite and is one of the simplest to understand.
You need to learn very well and practice, before you can start teaching others.
Without knowing exactly how to correctly help yourself there is a high chance that you can cause more damage than do any good to those who are in need of some help.
Trying to help someone else before you assured that you are out of danger might bring you in a situation where you not only cant deliver the support to the others but would need help yourself and someone else would need to assign resources to get you and the others out of troubles.
This, by all means, doesn't say "do not risk anything". When someone needs help, please go and help, but calculate the risks and make sure you can do it and are able to complete the task, before moving into a situation.
Unfortunately there are too many teachers without good knowledge base..