Matthew Henry Commentary Isaiah 25:9-12

"And it shall be said in that day, Lo, this is our God; we have waited for him, and he will save us: this is Jehovah; we have waited for him, we will be glad and rejoice in his salvation. For in this mountain will the hand of Jehovah rest; and Moab shall be trodden down in his place, even as straw is trodden down in the water of the dung-hill. And he shall spread forth his hands in the midst thereof, as he that swimmeth spreadeth forth [his hands] to swim; but [Jehovah] will lay low his pride together with the craft of his hands. And the high fortress of thy walls hath he brought down, laid low, and brought to the ground, even to the dust." — Isaiah 25:9-12 (ASV)

With joy and praise will those who looked for the Redeemer welcome the good news of him; and with a triumphant song, glorified saints will enter into the joy of their Lord. And it is not in vain to wait for him, for mercy comes at last, with abundant reward for the delay.

The hands once stretched out on the cross to make way for our salvation will eventually be stretched forth to destroy all impenitent sinners. Moab here represents all adversaries of God's people; they will all be trodden down or threshed. God will bring down the pride of the enemies by one humbling judgment after another. This destruction of Moab is symbolic of Christ's victory and the pulling down of Satan's strongholds.

Therefore, beloved brothers, be steadfast, unmovable, always abounding in the work of the Lord; for your labor is not in vain in the Lord.