Jamieson, Fausset and Brown on Micah 5:7

7. remnant of Jacob--already mentioned in Mi 5:3. It in comparative smallness stands in antithesis to the "many people." Though Israel be but a remnant amidst many nations after her restoration, yet she shall exercise the same blessed influence in quickening them spiritually that the small imperceptible dew exercises in refreshing the grass (De 32:2; Psa 72:6; 110:3). The influence of the Jews restored from Babylon in making many Gentile proselytes is an earnest of a larger similar effect hereafter (Is 66:19; Zec 8:13).

from the Lord--Israel's restoration and the consequent conversion of the Gentiles are solely of grace.

tarrieth not for man--entirely God's work, as independent of human contrivance as the dew and rains that fertilize the soil.