Gemara:

Shabbat 

Halacha:

Shabbat,  Tefillah 

Machshava:

Shabbat,  Tefillah 

References: Shabbat: 33B ,  Shabbat: 69B  

Description

In the one passage that doesn't change on Shabbat from night to day to afternoon [i.e. אלו-הינו ואלו-הי אבותינו רצה], there is a WORD that does change: at Maariv, we say וינוחו בה and at Shacharit, we say וינוחו בו. Is this just a SMALL variation, or perhaps a MAJOR change in mood and charachter?