Tafsir

The Jews used to say sarcastically that their hearts were "veiled", by which they meant that their hearts were so well protected against Islam that it could never touch them. This was their way of congratulating themselves on being staunch in their belief. The Holy Qur'an points out that this is not the firmness of faith, but a damnation, for they deny Islam which now is the true religion, and stick to a religion which has been abrogated. They, consequently, possess only "a little" faith ('Iman ایمان). Since a little faith is not acceptable, they turn out to be infidels.

The little “ faith" which they possessed pertained to the doctrines which are common to Islam and Judaism - for example, belief in Allah, or belief in the Day of Judgment. But they did not accept Sayyidna Muhammad ﷺ as a prophet, and the Holy Qur'an as the Word of Allah. So, their faith was not complete.

If the Verse describes 'the little faith' as 'Iman ایمان ، it does so only in the lexical sense, for 'Iman ایمان signifies total certitude, even if it pertains to certain things, and not to others. But from the point of view of the Shari'ah, such a partial faith cannot be described as 'Iman ایمان . The Shari` ah would accept as valid only that 'Iman ایمان which affirms with certitude each and everything that the Shari` ah requires one to affirm.