Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him) said:
Allah Almighty says:
“So judge between them by what Allah has revealed and do not follow their inclinations away from what has come to you of the truth. To each of you We prescribed a shir`ah (law) and a minhaj (clear way).” [Al-Ma’idah 5:48]
So He commanded him to judge by what Allah revealed to those before him. For each of the two messengers (Musa and `Isa) and two books (Tawrah and Injil), We have prescribed a shir`ah and a minhaj, i.e. a law and clear way; for shir`ah is shari`ah which is a law, and minhaj is a clear way.
[Majmu` al-Fatawa (19/113)]
الشريعة والمنهاج شريعة ومنهاجا وبيان معنى ذلك.