I need little help to understand this paragraph. (cp 14)

142 Legality For a contract to be valid and enforceable, it must be formed for a legal purpose. A contract to do something that is prohibited by federal or state statutory law is illegal and. as such, void from the outset and thus unenforceable. Additionally, a contract to commit a tortious act [such as an agreement to engage in defamation or fraud] is contrary to public policy and therefore illegal and unenforceable