What is the ruling on one who does not read the Prophetic hadiths and is not concerned with studying them, and how can he be a believer in what came from the Prophet?

Seeking religious knowledge is an obligation upon every Muslim. What exceeds this obligatory knowledge is a communal obligation (fard kifayah). A student of knowledge should exert effort in learning matters of the Sharia (definition) and perusing books of Sunnah (definition) and Hadith (definition). However, specialization in the science of Hadith is not an obligation upon every individual; each student of Islamic law has an area of specialization. An ordinary person is not required to dedicate themselves entirely to knowledge but should ask the people of remembrance. Faith in what the Prophet, peace and blessings be upon him, brought is achieved by believing what has been authentically reported from him, obeying him in what he legislated, and refraining from what he forbade. The path to all of this is learning and gaining a deep understanding of the religion by reading the Book and the Sunnah or by asking the people of knowledge.