The Re Davis case of 1630, the John Punch case of 1640, the John Casor case of 1654, and the Elizabeth Key case of 1655-1656 each individually pushed for the creation of new laws in Virginia which allowed for African slavery. These cases all clearly contributed to the enforcement of new legalized African slavery laws.
Bibliography:
US History. (2008). Indentured Servants. http://www.ushistory.org/us/5b.asp
Shefveland, K. (2016). Indian Enslavement in Virginia. https://www.encyclopediavirginia.org/Indian_Enslavement_in_Virginia
Anderson, P. (2012). Supporting Caste: The Origins of Racism in Colonial Virginia. http://scholarworks.gvsu.edu/cgi/viewcontent.cgi?article=1009&context=gvjh
Pbs.org. (2004). The Slave Experience: Responses to Enslavement. http://www.pbs.org/wnet/slavery/experience/responses/spotlight.html
History in an Hour. (2011). The "first slave" - the case of John Casor - History in an Hour. http://www.historyinanhour.com/2011/03/08/the-first-slave-john-casor/ [Accessed 8 Oct. 2017].
Banks, T. (n.d.). Subjecthood And Racialized Identity In Seventeenth Century Colonial Virginia. [online] Dangerous Woman: Elizabeth Key's Freedom Suit.