Cat Stevens is now Youssef Islam.
The Jewish Sabbath is from sundown on Friday to sundown on Saturday.
A devout catholic can attend mass twice a day or more, for 7 days a week.
I think that Moslems are supposed to pray 5 times a day, but I'm not 100% certain.
We have the Free Church of Scotland known as The Wee Frees, which believes in total observation of the sabbath, and does not use musical instruments in the church. They use a system like the Jewish cantor, where someone leads off the hymn, and the rest join in. Gaelic hymn singing is an amazing thing to hear, and I recommend it to all folkies as being well worth the listen.
Giok