Email a post on specified date

Hi

I’m working on a charity website that has daily devotions.
The people want to be able to enter in a months worth of daily devotions, but only show one, a day at a time. I’ve worked out how to do that with some php coding – which is then displayed on the website.
Now what they would like is for people to “subscribe” to the daily devotion and receive an email each day with that day’s devotion (so when that day’s devotion is displayed on the website it also needs to get email to whoever subscribed to the devotions).
I can’t seem to find a plugin that could help me with this and not sure if I could actually code this?