The Zohar in parashat Mishpatim mainly focuses on the topic of reincarnation. The Zohar starts with the concept of slavery, but not the commonly concept known as slavery. The Zohar refers to slavery as the slavery humans have to the Yetzer Hara (inclination towards wrong doing). Chazal (the sages of blessed memory) tells us that there is no freedom only through the learning f the Torah. So the Torah is the gateway for spiritual and physical freedom. 

The Zohar specifies that when it says in the Torah: 

כִּ֤י תִקְנֶה֙ עֶ֣בֶד עִבְרִ֔י שֵׁ֥שׁ שָׁנִ֖ים יַעֲבֹ֑ד

When you acquire a Hebrew slave, he shall serve six years… (Exodus 21:2)

It does not mean only about the physical 6 years the Torah is talking about. It also refers to the neshama (soul) that is coming in a reincarnation. The 6 years refer to the 6 edges of this world: North, South, East, West, Up and Down; the area known by science as space. All of the lifetimes that a soul experiences happens within this space spectrum, which has a spiritual and a physical realm. So, what is real freedom? According to the Zohar, it is the neshama that is related to the shvi’it (concept of 7). As the Torah says: 

וּבַ֨שְּׁבִעִ֔ת יֵצֵ֥א לַֽחׇפְשִׁ֖י חִנָּֽם....