وَبَعْدُ
After the praise and blessings, the main discussion begins.
فَإِنَّ مَبْنَى عِلْمِ الشَّرَائِعِ وَالْأَحْكَامِ
For the study of religious prescriptions and rulings rests upon a foundation.
Mabnā is the foundation upon which a structure rests. Sharāʾiʿ, plural of sharīʿah, concerns divinely prescribed paths and religious law; aḥkām refers to rulings. Here the issue is what makes the study of these rulings authoritative.
To accept a command such as the obligation of prayer as God's command, one must first affirm that Allah is the true Lord and that His guidance has been reliably communicated through the Messenger. Doctrinal foundations therefore underlie the study of practical law.
Distinction: The particular obligations of prayer are treated in fiqh; the authority of divine command and truthfulness of prophethood are foundational questions of creed.