John Gill Commentary Zechariah 8:12

"For [there shall be] the seed of peace; the vine shall give its fruit, and the ground shall give its increase, and the heavens shall give their dew; and I will cause the remnant of this people to inherit all these things." — Zechariah 8:12 (ASV)

For the seed [shall be] prosperous
Being cast into the earth, it shall spring up again, and produce a large increase; whereas before, though they sowed much, it came to little, (Haggai 1:6).

the vine shall give her fruit ;
be loaded with clusters, and produce large quantities of wine; whereas before there were used to be had fifty vessels out of the press, there were but twenty, (Haggai 1:11) (2:16). and the ground shall give her increase ;
as usual, meaning of wheat and barley; whereas before there used to be a heap of twenty measures, there were but ten, (Haggai 1:11) (2:16). and the heavens shall give their dew ;
which makes the earth fruitful; whereas before the heaven over them was kept back from dew, and instead of it were blasting, mildew, and hail, (Haggai 1:10) (2:17).

and I will cause the remnant of this people to possess all these
[things] ;
as a symbol of better things inherited by the remnant according to the election of grace; and who have the promise both of this life and that to come; and who, seeking in the first place spiritual things, have all others added to them, convenient for them.