I resolved to present a concise book containing the essence of the obligatory acts of worship that a Muslim must not be ignorant of, in a simplified style. I compiled this book, making it light and comprehensive, free of boring prolixity and insufficient detail, so that the reader can quickly draw from it. I have diversified it with the finest traditions, the core principles, and the biography of the Prophet (peace and blessings be upon him), along with examples, situations, and solutions, so that the traveler can travel with it and the present can rise above it. The reader will learn the difference between habitual acts and the essence of worship, while recognizing what is most important and significant, with a gradual progression of knowledge. I have titled it "The Security of the Shari'ah."