The main definition of the idiom part and parcel is a basic or essential part. The phrase has been around at least since the 16th century. Back then, parcel meant an essential component, so part and parcel were roughly synonymous. The phrase apparently began as legal jargon, where this kind of overemphatic wordiness is common. Indeed, most early instances of part and parcel are from legal texts, and the phrase didn’t enter broader usage until the 19th century.
Overcoming mid-race difficulties are part and parcel of a jumps jockey’s lot. [The Age]
These men weren’t battlers like Papp, but they knew that a degree of unpopularity was part and parcel of public life. [Los Angeles Times]
Ever since Tolstoy challenged Turgenev to a duel, the vendetta has been part and parcel of literary life. [Guardian]