If Israel has chemical weapons it would prudent for them to destroy them. I have not seen clear evidence that Israel has chemical weapons.
Supposing though that Israel does have chemical weapons; if one is going to hold Israel to the same standard as Syria then they should know that no one forced Syria to give up chemical weapons, but rather that the Assad regime agreed on its own volition to destroy its chemical weapons. The UN cannot make any nation do anything. The UN can only oversee and aid in such an action if it is chosen.
Supposing though that Israel does have chemical weapons; if one is going to hold Israel to the same standard as Syria then they should know that no one forced Syria to give up chemical weapons, but rather that the Assad regime agreed on its own volition to destroy its chemical weapons. The UN cannot make any nation do anything. The UN can only oversee and aid in such an action if it is chosen.