Hawzah News Agency – Imam al-Sadiq (AS) said, my father (AS) used to say:

إنّهُ لَيس مِن عَبدٍ مؤمنٍ إلّا و في قَلْبهِ نُورانِ: نورُ خِيفَةٍ ونورُ رَجاءٍ، لَو وُزِنَ هذا لَم يَزِدْ على‏ هذا، ولَو وُزِنَ هذا لَم يَزِدْ على‏ هذا.

'There is no believing servant except that in his heart are two lights, a light of fear and a light of hope, if they were each to be measured neither would exceed the other.'

Source: al-Kafi, v. 2, p. 67, no. 1