Shemini, Chapter 1
1) (Vayikra 10:12): "And Moses spoke to Aaron and to Elazar and Ithamar his sons": His sons were equal to him in (deserving) honor and they were equal to him in keeping silent (viz. Vayikra 10:3). I might think that his first sons, too, (Nadav and Avihu) were equal to him in honor. It is, therefore, written (of Elazar and Ithamar) "his remaining sons." His remaining sons were equal to him in honor, but not the first ones.