This is a multi-factored question. It involves power, money, capabilities, and social/religious views. The most powerful countries in the Arab world (Such as Saudi Arabia) do not like the Palestinian cause as it threatens the Saudi Royal Family. read more
Then you have countries such as Algeria and Jordan, which give Palestine a lot of diplomatic support, however they don’t have enough resources to do much else other than that. Although Lebanon is strapped, it provide moral and diplomatic support to Palestinians, again due to the lack of resources. read more