A friend told me some answers I dont know where but I know  who said them.

1)** Siddur Yavetz** on bentching says what I consider the best answer that when Mosiach comes the land of Israel will expand VIDUK

2)I think the Haemek Davar says our minds will become more expansive (I guess the eretz is the mind?! then I have to see that one 

3)He said the Ramban on the Posuk has two answers but i don't remember them i will edit later