Shabba is a term that is used as a nickname of sorts for the concept behind Shabbat, the Jewish day of rest in which an observant Jew cannot work. On Shabbat, the day of rest, Jewish people do more than just sleep in late as they have time to set aside to appreciate the wonders of the world and reflect on their path with God.
Shabbat is modeled after the rest that God took in Genesis 2:1-3 where it says, "The heaven and earth were finished, an all their array. On the seventh day God finished the work which God had been doing, and God ceased (or rested) on the seventh day from all the work which God had done. And God blessed the seventh day and declared it holy, because on it God ceased (or rested) from all the work which God had done." This pattern of working and resting was adopted by all followers of God.
This kind of rest has been thought to be a time for reflection and to rekindle spirit as well restore the soul. Shabbat is also a resting holiday that is mentioned in the Ten Commandments. It is asked that the believers remember the sabbath day and keep it holy by not doing any labor on that day.