It is between Egypt and Israel. In Egypt Moses would be honored (to be called the son of Pharaoh’s daughter) and enjoy luxury. In Israel Moses would be mistreated as a slave with his people. He would share in the reproach of his people. It would be a sin (Hebrews 11:25) not to side with God’s people.
24 C'est par la foi que Moïse, devenu grand, refusa d'être appelé fils de la fille de Pharaon;