And I will set his hand in the sea. The vast extent of the kingdom is here adverted to. As the people by their wickedness had, as it were, blocked up the way, and intercepted the blessing of God, their inheritance was more limited than the promise implied. But now God declares, that during the reign of David, it will be again enlarged, so that the people shall possess the whole country, from the sea even to the river Euphrates. From this we gather, that what God had promised by Moses was fulfilled only in the person of David, that is to say, from his time. By the rivers may be understood, either the Euphrates alone, which is cut into many channels, or the other neighboring rivers on the coast of Syria.

I will set his hand also in the sea - His dominion shall extend from the sea on the one hand to the rivers on the other. The sea here evidently refers to the Mediterranean; and the rivers to the great rivers on the east - the Tigris and Euphrates. These were the promised boundaries of the land. Genesis 15:18. David secured a conquest over all these territories, and united all under his scepter, thus securing the accomplishment of the promise made to Abraham. See the notes at Psalm 60:1-12.

I will set his hand also in the sea - This was literally fulfilled in David. Hand signifies power or authority; he set his hand on the sea in conquering the Philistines, and extending his empire along the coast of the Mediterranean Sea, from Tyre to Pelusium. All the coasts of the Red Sea, the Persian Gulf, and the Arabic Ocean, might be said to have been under his government, for they all paid tribute to him or his son Solomon.
His right hand in the rivers - First, the Euphrates: he subjected all Syria, and even a part of Mesopotamia; 2-Samuel 8:3; 1-Chronicles 18:3. He also took Damascus, and consequently had his hand or authority over the river Chrysorrhoes, or Baraddi; and in his conquest of all Syria his hand must have been on the Orontes and other rivers in that region. But if this be considered as referring to the typical David, we see that He was never conquered; he never lost a battle; the hosts of hell pursued him in vain. Satan was discomfited, and all his enemies bruised under his feet. Even over death he triumphed; and as to his dominion, it has spread and is spreading over all the isles of the sea, and the continents of the world.

I will set his hand also in the sea, and his right hand in the (x) rivers.
(x) He will enjoy the land around him.

I will set his hand also in the sea,.... Which is expressive not of his dominion over the sea, and of his power and authority over all things in it, which: he has by right of creation, and as Mediator, Psalm 8:5, of which there were instances in the days of his flesh, Matthew 8:26, but of his kingdom taking place in, and of his government over the inhabitants of the isles of the sea; and so the Targum,
"I will set or place his government in the provinces of the sea;''
and which has been remarkably accomplished in our isles, where his Gospel has been preached, his kingdom set up, and he has had a race of subjects, and a seed, to serve him for many years:
and his right hand in the rivers: or, as the Targum,
"the power of his right hand in those that dwell by rivers;''
meaning such that dwell upon the continent, afar off from the sea, and whose countries are watered by rivers: so that both phrases denote the extent of Christ's kingdom in the continent, and in the islands of the sea; signifying, that it should reach everywhere, and be from sea to sea, and from the river to the ends of the earth, Psalm 72:8. Compare with this Revelation 10:1. Aben Ezra interprets it of David's prevailing over those that go in ships in the sea, and in rivers.

hand [and] right hand--power (Psalm 17:7; Psalm 60:5).
sea, and . . . rivers--limits of his empire (Psalm 72:8).

Set - Establish his power and dominion. The sea - The mid - land sea. The rivers - Euphrates, called rivers, in regard of divers branches of it, and rivers which flow into it. So here is a description of the uttermost bounds of the promised land.