Says the Shaykh Abu Ja'far: Our belief concerning this is the reply of (Imam Ja'far) as-Sadiq to Zurara when he was asked: What do you say, O my Leader, concerning destiny (qada) and decree (qadar)? He said: I say that when Allah will collect the slaves on the Day of Resurrection, He will ask them concerning what He had enjoined on them, and will not question them concerning what He had destined for them.2
Now discussion about (Allah's) decree is prohibited; for the Prince of Believers, when questioned about the decree replied: It is a deep sea, do not enter into it. Then the man asked him a second time and he replied: It is a dark path, do not traverse it. Then he asked him a third time and he said: It is a secret of Allah, do not speak about it.3
And the Prince of Believers, on whom be peace, said concerning the decree (qadar): Lo! Verily, qadar is a secret of Allah's secrets, and a veil of Allah's veils, and a guarded thing4 within Allah's guarded thing, being raised within the veil of Allah5 concealed from Allah's creatures and sealed by the seal of Allah.
Among the things within the knowledge of Allah, it has priority (over all others). Allah has exonerated His slave from its knowledge, and elevated it beyond the ambit of their perception and reason. They cannot attain to (a knowledge) of its divine nature, or its eternal power, or its refulgent greatness, or the glory of its oneness; for this (knowledge of qadar) is a raging sea, exclusive to Allah, the Mighty and Glorious.6
Its depth is the distance between the heavens and the earth; its width, the distance between the east and the west; it is dark as a starless night; full of snakes and fishes, which at one time come up to the surface, and at others go down into the bottom of the sea.
At the bottom (of that sea) there is a shining sun. It does not befit any one to seek knowledge of it (the sun), except the One, the Matchless, the Everlasting. He who tries to seek knowledge of it, contravenes Allah in His command, and disputes His sovereignty, and probes into His secret and His veil.7 And (thereby)
“He shall incur the wrath of Allah: Hell shall be his abode and wretched the journey thither”8 (Qur'an 8:16).
And it is related that once upon a time the Prince of Believers, on whom be peace, avoided a slanting wall and went to the other side. He was asked: O Prince of Believers, do you run from the destiny (qada) of Allah? He replied: I run from the destiny (qada) of Allah to His decree (qadar).
And (Imam Ja'far) as-Sadiq was asked concerning charms (ruqya, plural ruqan), whether to some extent they avert Allah's decree (qadar). And he replied: They form part of (Allah's) decree.9