Here's why:
* Early Scribes: While Muhammad (PBUH) received revelations, he wasn't initially literate. Early scribes like Zaid ibn Thabit (RA) and Abu Bakr (RA) played a vital role in writing down the revelations.
* Hazrat Ali's Role: Hazrat Ali, known for his exceptional memory and intelligence, was also a scribe. He was especially trusted by the Prophet (PBUH) and often took notes during revelations. He also helped with the compilation of the Quran after the Prophet's death.
* The Term "Katib e Wahi": The term "Katib e Wahi" specifically refers to someone who actively participates in the process of receiving revelation, understanding its meaning, and writing it down. Hazrat Ali's role in understanding and interpreting the revelation, along with his skill as a scribe, led to him being recognized as the first "Katib e Wahi".
It's important to note that some scholars might consider other early scribes as "Katib e Wahi", but Hazrat Ali's close relationship with the Prophet (PBUH) and his unique position as a scribe and interpreter make him stand out.