Arabic Language Packs for SharePoint 2013
Language packs enable creation of sites and site collections in multiple languages without requiring separate installations.
Arabic Language Packs for SharePoint Foundation 2013
https://www.microsoft.com/en-us/download/details.aspx?id=35492
Arabic Language Packs for SharePoint Server 2013 [Yet Not publicly published but I have downloaded from my MSDN Subscription]
[Updated] - Published to the following URL