The Exalted said: “He is the First (nothing is before Him) and the Last (nothing is after Him)”. (Al-Hadid: 3)
P.B.U.H. said: “God, You Are the First, for there is nothing before You, and You Are the Last, for there is nothing after You.”
God, glorified be Him, is the First: without a beginning, for there was nothing before Him or with Him; He precedes all things in existence by His Perfect Essence, High Stature and Attributes. He is also the Last: after everything, without an end to His Perpetual Existence and Descriptions. Being the First, means that He is the Cause of every boon, and being the Last indicates that He is the Ultimate Aim that creatures resort to for their needs and worship. Worshipping Him by His Name (The First) necessitates avoiding searching for the causes, because He starts giving favors without any means of the slave, and worshipping Him by His Name (The Last) means not trusting the causes (not trusting them by themselves only) because they will eventually vanish and only remains the Permanent, Who exists after them all.