Bin Laden also condemns Arab governments for preventing their people from acting to "liberate Palestine."
The tape was posted Wednesday on Islamic militant Web sites where al-Qaida usually issues its messages. The authenticity of the tape cannot be independently confirmed. But the voice resembles that of bin Laden in previous messages.
The Israeli air and ground offensive to stop rocket fire from Gaza's Hamas rulers is in its 19th day. Palestinian health officials estimate more than 940 Palestinians, half of them civilians, have died.