Sforno on Numbers 13:16/ספורנו על במדבר י״ג:ט״ז

1ויקרא משה להושע בן נון יהושע, the Torah means that this man was known as a man of valour by the name of Hosheah among the members of his tribe. The fact that he has been referred to as “Joshua” already in Numbers 11,28 is because in his capacity as Moses’ personal valet Moses had changed his name in the form of a prayer asking that he be the instrument of his own salvation and that of others.