All these are so many different expressions, to intimate that the Lord's mercy to his people is all of grace, and not for their deserts. The Lord watcheth over them for good; but it is for the exaltation of his free grace.
Related Commentaries of Isaiah 27:6
Isaiah 27:6-10
6 He shall cause them that come of Jacob to take root: Israel shall blossom and bud, and fill the face of the world with fruit.
7 Hath he smitten him, as he smote those that smote him? or is he slain according to the slaughter of them that are slain by him?
8 In measure, when it shooteth forth, thou wilt debate with it: he stayeth his rough wind in the day of the east wind.
9 By this therefore shall the iniquity of Jacob be purged; and this is all the fruit to take away his sin; when he maketh all the stones of the altar as chalkstones that are beaten in sunder, the groves and imagesc shall not stand up.
10 Yet the defenced city shall be desolate, and the habitation forsaken, and left like a wilderness: there shall the calf feed, and there shall he lie down, and consume the branches thereof.