Israel was created in 1948 by the United Nations which is an organization that represents the world community, including Israel's adversaries. As such, a reasonable argument can be made that Israel is the world's most legitimate country. Whereas most countries were established by people who settled in a place, (i.e. the United States, Canada, Mexico), or are native to a place, (England, France, Italy), Israel was established and legitimized by the World Community. You don't get more legal than that! That said it wouldn't hurt Abbas to say that he accepts Israel as the state of the Jewish people and thereby neutralize Bibi's argument. If he wants the imprimatur of legitimacy for his state from the UN then he's going to have to fully recognize the legitimacy of Israel, a UN member state just like the other 191 member states that Abbas has no problem with.
Kerry raises South China Sea concerns with China's Wang (Reuters)