The relation between these two countries Israel And Palestine are not good from the mid 20th century. And now till 2013 there are many factors which has been added and although the peace process during these years has been fluctuating. Their conflict has formed the core part of the wider Arab–Israeli conflict.
At present the violence among the civilians of these countries has added some fire in the conflict between these countries.

To know the conflict in detail read this :- http://en.wikipedia.org/wiki/Israeli%E2%80%93Palestinian_conflict