Allāh (swt) says: “Allāh is the light of the heavens and the earth. The parable of His Light is a niche wherein is a lamp, the lamp is in a glass, the glass as it were a glittering star lit …” (Q24:35) 
Ali ibn Ja’far said, I asked Abā al-Hasan (al-Kāẓim) (a) about 
the [meaning of] words of Allāh: ‘a niche where there is a lamp…’ He (a) said: ‘the niche is Fāṭimah (sa), the lamp is al-Hasan (a) and 
al-Husayn (a) is the glass.’ About the phrase ‘as it were a glittering star lit’ he said: ‘Fāṭimah (sa) was like a shining star among the women of the worlds...’ and about ‘whose oil almost lights up’ he said: ‘knowledge was about to flow forth from her.’ 
In another similar narration, the Holy Prophet (saww) said: ‘and the light of my daughter Fāṭimah is from the light of Allah (swt).  (Bihar al-Anwar vol. 15 pg. 10)
Fatimah al-Zahra (a) from the Cradle to the Grave