What is the difference between the science of Nahw (syntax) and the science of Sarf (morphology), what is the benefit of each to Sharia, and what are the most important books in each science?

The difference between Nahw (syntax) and Sarf (morphology) is that Nahw investigates the conditions of the endings of words in terms of their inflection (i'rab) and immutability (bina'), whereas Sarf investigates the word itself, its derivation, and its conjugation. The benefit of both lies in rectifying the tongue and correctly understanding the Book of Allah, the Sunnah of His Prophet, and the speech of people. Among the recommended books for Nahw are: Al-Ajurrumiyyah, Mulhat al-I'rab, Qatr al-Nada, and Ibn 'Aqil's commentary on Al-Alfiyyah. For Sarf: Ibn 'Aqil's commentary on Al-Alfiyyah, Shadhaa al-'Arf, and Lamiyyat al-Af'al.