Variantly: "as se'irim upon the herbage": Just as se'irim descend upon the grass and cause it to grow, producing (all varieties:) red, black, and white, so, words of Torah (produce all varieties of men:) rabbis, pious laymen, sages, tzaddikim (righteous ones) and chassidim (saintly ones).
Variantly: "My taking shall drip as the rain": Just as the rain is not seen until it comes, viz. (I Kings 18:45) "It happened in the meantime that the heavens had darkened with clouds and (filled) with wind, and there was a great rain" — so Torah scholars are not known until they teach Mishnah, halachoth, and aggadoth, or until they are appointed community leaders.