This statement has always bothered me. I didn't figure out why until today.
Really, it's one of the sneakiest dictums of our society--because it isn't understood. The problem with putting others first is we only look at the short term. We actually do damage to ourselves by tending to the urgent, visible needs of others over our own well being. Yes, we should serve our fellow humans. You can’t serve others, however, if you don’t take care of yourself.
As writers, we take care of ourselves when we write.
If you'd like more on this topic, send me an email and I'll forward what I wrote today about Putting Others First, in my chapter "Breaking Rules."