And when all the congregation saw that Aaron was dead
Not that they saw his dead body, but they perceived by the relation of Moses, and by various circumstances, as not seeing Aaron come down, whom they saw go up, and seeing Eleazar with Aaron's garments on him, and perhaps by tokens of mourning in Moses and Eleazar; so the Targums of Jonathan and Jerusalem say, they saw them come down from the top of the mountain, with their garments rent, and ashes on their heads, weeping and lamenting:
they mourned for Aaron thirty days;
the whole month out; so long public mourning with the Jews lasted, as Josephus F13 relates:
[even] all the house of Israel;
men and women, as the Targum of Jonathan, and so Jarchi: no doubt it was for the amiable virtues and abundant grace that were in him, and the many services he had done for them, both before and since he was invested with the priestly office; and oftentimes the memory of such things is revived after the death of a good man, which are not so much taken notice of in his life, nor he be thanked for them, or have honour and respect shown him on account of them; but when dead, he, and what he has done, are spoken well of, and his loss lamented.
F13 De Bello Jud. l. 3. c. 8. sect. 5.