Hebrews 1:2

Heb. 1:2. Hath in these last days spoken unto us by (his) Son, whom he hath appointed heir of all things, by whom also he made the worlds;

It was one of Edwards' major arguments (in his Humble Attempt), for world prayer for the advancement of Christ's kingdom that He was prophesied here and elsewhere in Scriptures to be the "heir of all things."

[I]t is natural and reasonable to suppose, that the whole world should finally be given to Christ, as one whose right it is to reign, as the proper heir of him, who is originally the king of all nations, and the possessor of heaven and earth: and the Scripture teaches us, that God the Father hath constituted his Son, as God-man, and his kingdom of grace, or mediatorial kingdom, to be the heir of the world, that he might in this kingdom have the heathen for his inheritance, and the utmost ends of the earth for his possession; Hebrews 1:2, and Hebrews 2:8 Psalms 2:6-8. Thus Abraham is said to be the heir of the world, not in himself, but in his seed, which is Christ, Romans 4:13. And how was this to be fulfilled to Abraham, but by God's fulfilling that great promise, that in his seed all the nations of the earth should be blessed? For that promise is what the apostle is speaking of; which shows, that God has appointed Christ to be the heir of the world in his kingdom of grace, and to possess and reign over all nations, through the propagation of his gospel, and the power of his Spirit communicating the blessings of it. God hath appointed him to this universal dominion by a most solemn oath: Isaiah 45:23, "I have sworn by myself, the word is gone out of my mouth in righteousness, and shall not return, that unto me every knee shall bow, every tongue shall swear." Compared with Php_2:10-11. Though this solemn oath of God the Father is to be understood in some comprehensive a sense, as to extend to what shall be accomplished at the day of judgment, yet it is evident by the foregoing and following verses, that the thing most directly intended, is what shall be fulfilled by the spreading of the gospel of his salvation, and power of the Spirit of grace, bringing "all the ends of the earth to look to him that they may be saved, and come to him for righteousness and strength, that in him they might be justified, and might glory." God has suffered many earthly princes to extend their conquests over a great part of the face of the earth, and to possess a dominion of vast extent, and one monarchy to conquer and succeed another, the latter being still the greater; it is reasonable to suppose that a much greater glory in this respect should be reserved for Christ, God's own Son and rightful heir, who has purchased the dominion by so great and hard a service: it is reasonable to suppose, that his dominion should be far the largest, and his conquests vastly the greatest and most extensive. And thus the Scriptures represent the matter, in Nebuchadnezzar's vision, and the prophet's interpretation, Dan.2, "There the four great monarchies of the earth, one succeeding another, are represented by the great image of gold, silver, brass, iron and clay; but at last a stone cut out of the mountain without hands, smites the image upon his feet, which breaks the iron, clay, brass, silver and gold in pieces, that all becomes as the chaff of the summer threshing floors, and the wind carries them away, that no place is found for them; but the stone waxes great, becomes a great mountain, and fills the whole earth; signifying the kingdom which the Lord God of heaven should set up in the world, last of all which should break in pieces and consume all other kingdoms." Surely this representation leads us to suppose that this last kingdom shall be of vastly greater extent that any of the preceding. The like representation is made in the 7th chap. of Daniel. There the four monarchies are represented by four great beasts, that arose successively, one conquering and subduing another; the fourth and last of these is said to be dreadful, and terrible, and strong exceedingly, and to have great iron teeth, and to devour and break in pieces, and stamp the residue with his feet; yea, it is said, Daniel 7:22-23, that the kingdom represented by this beast shall devour the whole earth; but last of all one like the Son of Man appears, coming to the ancient of days, and being brought near before him, and receiving of him a dominion, and glory, and a kingdom, that all people, nations, and languages should serve him. This last circumstance, of the vast extent and universality of his dominion, is manifestly spoken of as one thing greatly distinguishing his holy kingdom from all the preceding monarchies: although of one of the former it was said, that it should devour the whole earth, yet we are naturally led, both by the much greater emphasis and strength of the expressions, as well as by the whole connection and tenor of the prophecy, to understand the universality here expressed in a much more extensive and absolute sense: and the terms used in the interpretation of this vision are such, that scarcely any can be devised more strong, to signify an absolute universality of dominion over the inhabitants of the face of the earth: Daniel 7:27, "And the kingdom and dominion, and the greatness of the kingdom under the whole heaven, shall be given to the people of the most high God. Agreeably to this the gospel is represented as preached unto them that dwell on the earth, and to every nation, and tongue, and kindred, and people, Rev. xiv.6. The universality of the prevalence of true religion in the latter days, is sometimes expressed by its reaching to "the utmost ends of the earth," Psalms 2:8. "To all the ends of the earth, and of the world," Psalms 22:27 Psalms 67:7 Psalms 98:3 Isaiah 45:22. "All the earth, with those that are afar off upon the sea," Psalms 65:5. "From the rising of the sun to the going down of the same," Psalms 113:3 Malachi 1:11, "The outgoings of the morning and of the evening," Psalms 65:8. It seems that all the most strong expressions, that were in use among the Jews to signify the habitable world in it utmost extent, are made use of to signify the extent of the church of God in the latter days: and in many places, a variety of these expressions is used, and there is an accumulation of them, expressed with great force.