Do not abandon anything of what Allah has made obligatory upon you in the Outward and the Inward. Whoever abandons the Outward after Allah has made known to him the Inward, Allah shall strip him of both the Inward and the Outward together."

From him [al-Sadiq] also, it is narrated that he said to Mufaddal bin Umar:

"O Mufaddal, enslave this Soul that incites to evil (Al-Nafs al-Ammara bi al-Su') by establishing discipline (Ta'dib). Whoever among you manifests anything contrary to what we manifest has indeed opposed us; and whoever opposes us has challenged us; and whoever challenges us—we shall be his adversaries and those who curse him, and Allah has prepared for him Hell, an evil destination."

"O Mufaddal, habituate yourselves to these commands in Seclusion (Al-Khala') so that you do not forget them in Public (Al-Mala'). Establish these obligations and disciplines and do not be negligent of them. Would any of you like to walk in the market naked?"

From him also, he said: "Indeed, the Prayer, Fasting, and the Major Ablution (Ghusl) from ritual impurity—these have Persons (Ashkhas); however, whoever does not act upon their Outward forms, the Inward shall not be accepted from him."

It was narrated regarding the saying of the Almighty: {And We taught him the craft of garments (san'ata labusin) for you} (Al-Anbiya: 80) that it refers to Dissimulation (Taqiya).