Like the breast of the waving and the right thigh — Of the peace-offering which is eaten by the kohanim, their wives, their children and their slaves for two days and one night. So may the firstborn animal be eaten for two days and one night.It shall be yours — Rabbi Akiva came and taught: [By repeating the words “shall be yours”] Scripture adds another ‘being,’ so that you should not say [that it is] like the breast and thigh of the thanksgiving offering, which is eaten only for [one] day and [one] night.

The Rashi