ציטירנדיקער פּירוש אויף דניאל 1:7

and he changed his name to Jehoiakim It is the custom of kings and princes to bestow a by-name upon their servants as they wish. An example is (Gen. 41:45): “And Pharaoh named Joseph, etc.,” and so (Num. 13:16): “and Moses called Hoshea the son of Nun, Joshua,” and so, (Dan. 1:7): “Now the chief officer gave them names, etc.” All this is to make known that he rules over him to name him as he desires.

ויקרא אלוקים ליום אור, you may ask yourself what possible need there was for G’d to call this light “day” already at the time He created it; however this is the way Moses worded it when he wrote down the Torah. Whenever, in Scriptures, G’d is recorded as mentioning “day” and “night,” as for instance in Genesis 8,22, where He made the promise that “henceforth the alternating manifestations of day and night will not cease to occur regularly,” יום ולילה לא ישבותון, this is a reference to the original light created on the first day. G’d always called this “light” “night and day.” Similarly, every time in this chapter when we encounter the expression ויקרא אלוקים, as well as when we read in Numbers 13,15 ויקרא אלוקים להושע בן נון יהושע, whereas the same man as representative of the tribe of Ephrayim had been referred to as הושע only 7 verses earlier as הושע. This was the same man, who, previously, when he appeared in his position of Moses’ personal valet was already known as יהושע, (Exodus 24,13) It is customary among kings that when they appoint a person to a position of eminence to signal this by changing the name of such a person. One well known example of this is Pharaoh calling Joseph צפנת פנח upon appointing him as viceroy of Egypt (Genesis 41,45) Other such examples are found in Daniel 1,7, etc.

והיה שמך אברהם, “henceforth your name will always be: Avraham.” It is an ancient custom to change someone’s name as a sign that he had received a promotion. We find this with Sarah, Yaakov, Joshua, as well as with Chananyah, Mishael, and Azaryah. (Daniel 1,7)