The deduction of a jurist is a proof of the authenticity of the Hadith
The 4 Imams have deduced from the previously mentioned Hadith. If a jurist (Mujtahid) performs a deduction based on the Hadith, then this is a sign of the Hadith’s authenticity and reliability. ‘Allama Ibn Nujaim Misri (May Allah shower His mercy on him) has written:
Translation: When a jurist performs a deduction from a Hadith, then this deduction is a sign that this Hadith is rigorously authenticated (Sahih). Therefore, after a deduction of a jurist, no other proof is needed for the reliability of a Hadith. (Al Bahr Ur Raiq Sharhu Kanz Ud Daqaaiq, Kitab Ul Bay’ah Faslun Yadkhulul Binaau Wal Mafateehu Fi Bai’ddaar)