Israel is likened to a vine in Psalm 80. The Psalm is actually speaking mainly about the Lost Ten Tribes ("EPHRAIM AND BENJAMIN AND MANASSEH" 80:2) and is worth reading: concerning the vine see verses 80:8-16. The boar who destroys [Psalms 80:13] it is actually Edom. The boar was a favorite symbol amongst early Celtic (especially on the Continent) and Germanic groups. Some of these were of Israelite origin and some were not, though they were related. The gods Essuvus amongst the Celts and some versions of Odin amongst the Germanics actually represent the ancestor-hero Esau.

Psalms 80
<<GIVE EAR, O SHEPHERD OF ISRAEL, THOU THAT LEADEST JOSEPH LIKE A FLOCK;   THOU THAT DWELLEST BETWEEN THE CHERUBIMS, SHINE FORTH. [80:1]
<<BEFORE EPHRAIM AND BENJAMIN AND MANASSEH STIR UP THY STRENGTH, AND COME AND SAVE US. [80:2]
<<TURN US AGAIN, O GOD, AND CAUSE THY FACE TO SHINE; AND WE SHALL BE SAVED. [80:3]
<<O LORD GOD OF HOSTS, HOW LONG WILT THOU BE ANGRY AGAINST THE PRAYER OF THY PEOPLE? [80:4]
<<THOU FEEDEST THEM WITH THE BREAD OF TEARS; AND GIVEST THEM TEARS TO DRINK IN GREAT MEASURE. [80:5]
<<THOU MAKEST US A STRIFE UNTO OUR NEIGHBOURS: AND OUR ENEMIES LAUGH AMONG THEMSELVES. [80:6]
<<TURN US AGAIN, O GOD OF HOSTS, AND CAUSE THY FACE TO SHINE; AND WE SHALL BE SAVED. [80:7]
<<THOU HAST BROUGHT A VINE OUT OF EGYPT: THOU HAST CAST OUT THE HEATHEN, AND PLANTED IT. [80:8]
<<THOU PREPAREDST ROOM BEFORE IT, AND DIDST CAUSE IT TO TAKE DEEP ROOT, AND IT FILLED THE LAND. [80:9]
<<THE HILLS WERE COVERED WITH THE SHADOW OF IT, AND THE BOUGHS THEREOF WERE LIKE THE GOODLY CEDARS. [80:10]
<<SHE SENT OUT HER BOUGHS UNTO THE SEA, AND HER BRANCHES UNTO THE RIVER. [80:11]
<<WHY HAST THOU THEN BROKEN DOWN HER HEDGES, SO THAT ALL THEY WHICH PASS BY THE WAY DO PLUCK HER? [80:12]
<<THE BOAR OUT OF THE WOOD DOTH WASTE IT, AND THE WILD BEAST OF THE FIELD DOTH DEVOUR IT. [80:13]
<<RETURN, WE BESEECH THEE, O GOD OF HOSTS: LOOK DOWN FROM HEAVEN, AND BEHOLD, AND VISIT THIS VINE; [80:14]
<<AND THE VINEYARD WHICH THY RIGHT HAND HATH PLANTED, AND THE BRANCH THAT THOU MADEST STRONG FOR THYSELF. [80:15]
<<IT IS BURNED WITH FIRE, IT IS CUT DOWN: THEY PERISH AT THE REBUKE OF THY COUNTENANCE. [80:16]
<<LET THY HAND BE UPON THE MAN OF THY RIGHT HAND, UPON THE SON OF MAN WHOM THOU MADEST STRONG FOR THYSELF. [80:17]
<<SO WILL NOT WE GO BACK FROM THEE: QUICKEN US, AND WE WILL CALL UPON THY NAME. [80:18]
<<TURN US AGAIN, O LORD GOD OF HOSTS, CAUSE THY FACE TO SHINE; AND WE SHALL BE SAVED>>. [80:19]

The grapevine is technically a tree. If the vine produces grapes then it is highly valued and this is the purpose for cultivating it. If the vine does not fulfill its purpose then it is useless, just a troublesome weed. Even for the most simple things, such as making a "pin" (i.e. peg or hook) to hang things on, its wood is useless since it is weak and unmanageable. Same thing for human beings, same thing for nations: We all have our task in this world. Equality means doing our own thing and not that of someone else.

The point is that to some degree we all have our own unique task in life. We have to do what we can with what we have as we are. We cannot look at other people and say that since they are getting along with what they are so should we do the same. Some people have been called to do certain things and this is why they were placed on this earth. A good doctor would not necessarily succeed if he had to do the job of a plumber and vice versa. As it is with individuals so it is with nations. The nation of Israel has its own unique task. The Ten Tribes have their task, Joseph amongst the tribes also has its unique goal. Judah has its obligation and the national proclivity that should enable it to fulfill itself. Even if you belief in Judaism that does not necessarily mean that you have to become Jewish.  Maybe God wants you to stay amongst "Joseph" and fulfill the purpose of your life in service to other Lost Israelites? It is not always easy to know what one's purpose should be in this world but we can do our best and God will guide us.

On the simple level the Prophet is speaking to the inhabitants of Jerusalem just before the destruction of the First temple by the Babylonians. Because the people had sinned and had not fulfilled their national obligation their Land would be destroyed, many would be killed, and the remainder exiled to other places. On the prophetic level the prophet is referring to all Israel and warning us (you and I together) to improve our ways for our own sake and the sake of others.