John 10:16 New King James Version (NKJV)
16 And other sheep I have which are not of this fold; them also I must bring, and they will hear My voice; and there will be one flock and one shepherd.
This has to do with the reuniting of the divided kingdom which division took place under Solomon's son Rehoboam and Solomon's servant Jeroboam. The kingdom was divided into the ten tribes in the north called Israel/Ephraim and two tribes in the south called Judah. The Davidic kingdom, being at hand during Christ's earthly ministry, would have developed into the fulfillment of prophecy for the nation to be reunited with all twelve tribes were it not for Israel's stubborn rejection resulting in the postponement of the kingdom and a halt of the prophetic program.
Eze 34:11 For thus saith the Lord GOD; Behold, I, even I, will both search my sheep, and seek them out.
Eze 34:12 As a shepherd seeketh out his flock in the day that he is among his sheep that are scattered; so will I seek out my sheep, and will deliver them out of all places where they have been scattered in the cloudy and dark day.
Eze 34:13 And I will bring them out from the people, and gather them from the countries, and will bring them to their own land, and feed them upon the mountains of Israel by the rivers, and in all the inhabited places of the country.
Eze 34:14 I will feed them in a good pasture, and upon the high mountains of Israel shall their fold be: there shall they lie in a good fold, and in a fat pasture shall they feed upon the mountains of Israel.
Eze 34:15 I will feed my flock, and I will cause them to lie down, saith the Lord GOD.
Eze 34:23 And I will set up one shepherd over them, and he shall feed them, even my servant David; he shall feed them, and he shall be their shepherd.
Eze 34:30 Thus shall they know that I the LORD their God am with them, and that they, even the house of Israel, are my people, saith the Lord GOD.
Eze 34:31 And ye my flock, the flock of my pasture, are men, and I am your God, saith the Lord GOD.
Eze 36:37 Thus saith the Lord GOD; I will yet for this be enquired of by the house of Israel, to do it for them; I will increase them with men like a flock.
Eze 36:38 As the holy flock, as the flock of Jerusalem in her solemn feasts; so shall the waste cities be filled with flocks of men: and they shall know that I am the LORD.
Eze 37:21 And say unto them, Thus saith the Lord GOD; Behold, I will take the children of Israel from among the heathen, whither they be gone, and will gather them on every side, and bring them into their own land:
Eze 37:22 And I will make them one nation in the land upon the mountains of Israel; and one king shall be king to them all: and they shall be no more two nations, neither shall they be divided into two kingdoms any more at all:
Eze 37:24 And David my servant shall be king over them; and they all shall have one shepherd: they shall also walk in my judgments, and observe my statutes, and do them.
Eze 37:25 And they shall dwell in the land that I have given unto Jacob my servant, wherein your fathers have dwelt; and they shall dwell therein, even they, and their children, and their children's children for ever: and my servant David shall be their prince for ever.
Recommended reading:
All of Ezekiel 34,36,37,38,39
Yet to be fulfilled.