Surah al-A'raf Ayah 8-9 says, “(Everyone's deeds) will certainly be weighed (and evaluated) on the Day of Judgment. Those whose good deeds weigh heavier than their bad deeds will have everlasting happiness. And whosoever scale be light, those are they who have ruined their selves for they used to be unjust unto Our Signs.”

Prophets and the Infallible Imams are the “Signs of Allah” Hence the people who were unjust to the Imams, their good deeds will not be accepted by Allah.

Surah al-Mu'minun Ayahs 102-103 says, “If the side of one's good deeds weighs heavier on a scale, he will have everlasting happiness, but if it weighs less, one will be lost forever in Hell.”

Surah al-Qa'riah Ayahs 6-11 says, “Those whose good deeds will weigh heavier (on the scale) will live a pleasant life, but those whose good deeds will be lighter (on the scale) will be thrown headlong into Hawiyah. What does it tell you it is? It is a burning fire.”

There are many interpretations of the balance; some say it is the balance like in this world. But since the balance in Qiyamat is a medium to identify faith and principles of belief, good and bad morals, righteous and evil deeds, it cannot be a physical balance. The Infallible Imam Ja'far al-Sadiq (a.s.) while replying to a question said, “Justice would be observed in accounting and recompense of deeds. The heavier deeds means more good deeds.” (Behar-ul-Anwar volume 7 page 248)

There are two alternatives; either it is the Shariat entailing correct belief and ethical values or the reflections of prophets and Imams. Since they were the guides of humanity and acted themselves according to the shariah and personified as perfect human beings, hence they may be considered as Scale.. At different occasions, the Noble Messenger (s.a.w.a.s.) said, “Justice, prayer and good behavior is the balance.” The Infallible Imam Ja'far al-Sadiq (a.s.) said, “One who recites 'there is no God except Allah' which should prevent him to commit prohibited acts, will enter Paradise.”

In yet another tradition, the Noble Messenger (s.a.w.a.s.) said, “I am the balance of knowledge and Ali is the two pans of the balance, Hasan and Husayn are its cords and Fatima is the connecting rod between them and the imams after Hasan and Husayn would be the criteria of recognition of their friends and their enemies.” (Bihar-ul-Anwar v. 23 p. 107)

Ahl-al-Bayt (a.s.), who were under the Cloak when the Ayah of Purity (33:33) was revealed, the Ayah certifies their Purity. Their Truthfulness was certified by Allah (s.w.t.) against the Christians of Najran when Ayah of Mubahelah was revealed (Surah Ale-Imran Ayah 61). They were the Signs of Allah.

There is another tradition of the Noble Messenger (s.a.w.a.s.) that if a Muslim, while praying in the Haram of Ka'ba and is fasting and gets killed without any fault of his but bears enmity with (Imam) Ali, he will not even smell the scent of Paradise.

It appears that the deciding factor of all deeds depends on the Wilayah of Imam Ali (a.s.) and his progeny (a.s.). in that their good deeds weigh heavier than the bad deeds and hence will guarantee their admittance to the Paradise.

Sources: The Glorious Qur'an (Urdu translation) by Ayatollah Naser Makarim Shirazi

                The Glorious Qur'an (English translation) by Ayatollah Agha H.M.M. Pooya Yazdi