This narration appears in Musnadul Firdaws on the authority of Sayyiduna Anas ibn Malik (radiyallahu ‘anhu). Rasulullah (sallallahu ‘alayhi wa sallam) said: “The virtue of Rajab over other months is like the virtue of the Quran over other speech.” (Musnadul Firdaws, Hadith: 4350)

However, ‘Allamah Suyuti (rahimahullah) has cited this narration in his book on fabricated Hadiths. Hafiz Ibn Hajar (rahimahullah) has declared a similar narration a fabrication. (Refer: Dhaylul La-Alil Masnu’ah, vol. 1 pg. 458, Hadith: 556, Tanzihush Shari’ah, vol. 2 pg. 160-161 and Tabyinul ‘Ajab, pg. 25, Hadith: 8)

The Hadith is therefore not suitable to quote.

And Allah Ta’ala Knows best

https://hadithanswers.com/the-virtue-of-rajab-over-the-other-months/
https://hadithanswers.com/an-unreliable-narration-on-spending-a-night-of-rajab-in-worship-and-fasting-the-next-day/