Why to never trust a Muslim:

Lying and cheating in the Arab world is not really a moral matter but a method of safeguarding honor and status, avoiding shame, and at all times exploiting possibilities, for those with the wits for it, deftly and expeditiously to convert shame into honor on their own account and vice versa for their opponents. If honor so demands, lies and cheating may become absolute imperatives.” [David Pryce-Jones, “The Closed Circle” An interpretation of the Arabs, p4]

“No dishonor attaches to such primary transactions as selling short weight, deceiving anyone about quality, quantity or kind of goods, cheating at gambling, and bearing false witness. The doer of these things is merely quicker off the mark than the next fellow; owing him nothing, he is not to be blamed for taking what he can.” [David Pryce-Jones, “The Closed Circle”, p38]

The word "Taqiyya" literally means: "Concealing, precaution, guarding.” It is employed in disguising one's beliefs, intentions, convictions, ideas, feelings, opinions or strategies. In practical terms it is manifested as dissimulation, lying, deceiving, vexing and confounding with the intention of deflecting attention, foiling or pre-emptive blocking. It is currently employed in fending off and neutralising any criticism of Islam or Muslims.

Lying and cheating in the Arab world is not really a moral matter but a method of safeguarding honor and status, avoiding shame, and at all times exploiting possibilities, for those with the wits for it, deftly and expeditiously to convert shame into honor on their own account and vice versa for their opponents.