Radak: I did all the guarding and tasks that one does for his vineyard. I hoped for good grapes - why did it make Be'ushim? Malbim - Verse 7 explains the Nimshal. Yisrael are the vineyard that Hashem planted. B'Keren Ben Shemen is Eretz ha'Kedoshah, prepared for people to attain all kind of perfection: (a) perfection of the Nefesh Bein Adam la'Makom, for it is prepared for Taharah, Kedushah and Nevu'ah; (b) perfection Bein Adam l'Chavero, for the land does not lack anything. There is no need to oppress, steal or encroach borders (infringe on another's income). Further - (a) Hashem made a fence to separate them from the idolaters around them, lest they mix with them. (b) He commanded to wipe out the Kena'ani amidst them, lest they entice them [to idolatry]. (c) He gave to everyone his own inheritance of field and vineyard by himself, so they can do Mishpat and Tzedakah and their minds will be free for Avodas Hashem. (d) He built a tower (the Beis ha'Mikdash) among them, to guard them from all afflicters and enemies. (e) He brought down Divine influence in exchange for their deeds - this is the wine, the anticipated end.