Jamieson, Fausset and Brown on Hebrews 11:23

23. parents--So the Septuagint has the plural, namely, Amram and Jochebed (Nu 26:59); but in Ex 2:2, the mother alone is mentioned; but doubtless Amram sanctioned all she did, and secrecy. being their object, he did not appear prominent in what was done.

a proper child--Greek, "a comely child." Ac 7:20, "exceeding fair," Greek, "fair to God." The "faith" of his parents in saving the child must have had some divine revelation to rest on (probably at the time of his birth), which marked their "exceeding fair" babe as one whom God designed to do a great work by. His beauty was probably "the sign" appointed by God to assure their faith.

the king's commandment--to slay all the males (Ex 1:22).