Dear all, c could anyone refer me to the origin of the phrase "meein olam haba... yom shabbat" outside of the zemer Ma Yedidut? I assume there are various places in Chazal where the Shabbat is referred to as an "extension" - for the lack of a better word - of the world to come, but would love to know where to start. Many thanks and apologies Simon Krysl