Shiekh Zainudin here says that studying these three basic branches of knowledge: Aqeeda (Islamic theology), Fiqh (Islamic jurisprudence) and Tasawwuf (Islamic mysticism) is the Fard Ain or personal obligation of every Muslim.
Sheik Zainuddeen explains in the above lines how to reach to the stage the Haqiqah with examples.
He also provoides examples for all three stages of Tawawwuf: Sharia, Tariqa and Haqiqa.
He compared Sharia with a ship and Tariqah with a sea and Haqiqah with a pearl.
Piety (Taqwa) is the backbone of all good deeds. Given the fact that this book Adhkia is dedicated to someone who wants to be Waliy (true believer with high rank), the author Sheikh Zainuddeen categorically begins the book with Taqwa, the highest character of a Muslim.