271 In that day the Lord with his sore and great and strong sword shall punish leviathan the piercing  serpent, even leviathan that crooked serpent; and he shall slay the dragon that is in the sea.
271 In that day, the Lord will punish with his sword- his fierce, great and powerful sword- Leviathan the gliding serpent, Leviathan the coiling serpent; he will slay the monster of the sea.
271 In that day the Lord with his hard and great and strong sword will punish Leviathan the fleeing serpent, Leviathan the twisting serpent, and he will slay the dragon that is in the sea.
271 At that time God will unsheathe his sword, his merciless, massive, mighty sword. He'll punish the serpent Leviathan as it flees, the serpent Leviathan thrashing in flight. He'll kill that old dragon that lives in the sea.
271 In that day the Lord with His severe sword, great and strong, Will punish Leviathan the fleeing serpent, Leviathan that twisted serpent; And He will slay the reptile that is in the sea.
271 In that day the Lord will take his terrible, swift sword and punish Leviathan, the swiftly moving serpent, the coiling, writhing serpent. He will kill the dragon of the sea.
Matthew Henry's Commentary on Isaiah 27:1
Commentary on Isaiah 27:1-5
(Read Isaiah 27:1-5)
The Lord Jesus with his strong sword, the virtue of his death, and the preaching of his gospel, does and will destroy him that had the power of death, that is, the devil, that old serpent. The world is a fruitless, worthless wilderness; but the church is a vineyard, a place that has great care taken of it, and from which precious fruits are gathered. God will keep it in the night of affliction and persecution, and in the day of peace and prosperity, the temptations of which are not less dangerous. God also takes care of the fruitfulness of this vineyard. We need the continual waterings of Divine grace; if these be at any time withdrawn, we wither, and come to nothing. Though God sometimes contends with his people, yet he graciously waits to be reconciled unto them. It is true, when he finds briers and thorns instead of vines, and they are set in array against him, he will tread them down and burn them. Here is a summary of the doctrine of the gospel, with which the church is to be watered every moment. Ever since sin first entered, there has been, on God's part, a righteous quarrel, but, on man's part, most unrighteous. Here is a gracious invitation given. Pardoning mercy is called the power of our Lord; let us take hold on that. Christ crucified is the power of God. Let us by lively faith take hold on his strength who is a strength to the needy, believing there is no other name by which we can be saved, as a man that is sinking catches hold of a bough, or cord, or plank, that is in his reach. This is the only way, and it is a sure way, to be saved. God is willing to be reconciled to us.