Don't be asinine. If the Israelis had wanted to grab land, they would have kept it all, and been perfectly within their rights to do so.
First, there is no "if" about it. They wanted to grab land and they did so by allowing the settlements. After the 1947 War, Israel doubled the original land given to them by UN Resolution 181 -- that's not enough? Too crowded? They need that extra 5% of the West Bank? C'mon.
Israel couldn't have "kept it all" because they couldn't have controlled it -- they have a problem controlling the 5% they did grab. The wall is testimony to that fact.
Lastly, Israel is not within their rights to do so. Not according to the 4th Geneva Convention and world opinion.