Ember Days or the Quatuor Temporas are a traditional time of harvest fasting “four times” per year. The Ember days are the Wednesday, September 19, Friday, September 21 and Saturday, September 22.
This is a time to ask God for the gift of holy priests for the harvest of souls. Let us voluntarily take up the Ember Days, whatever your intention may be.
For more on the Ember Days:
https://www.fisheaters.com/emberdays.html
http://catholicherald.co.uk/commentandblogs/2017/12/20/how-observing-the-ember-days-can-enhance-your-spiritual-life/