The verse establishes that fasting had been made obligatory for earlier believers, and that the aim behind it is to open their hearts to God and make them more conscious of Him. This, then, is the principal objective of fasting: to be God- fearing, or taqwā. Fasting, when observed in obedience to God and in pursuit of His pleasure, instils and revives this quality in the human heart and acts as a safeguard against evil and wrongdoing. True believers know and appreciate the value of being God-fearing in God’s sight. Hence, they constantly seek to enhance their sense of it. Fasting is a means to achieve just that.
In the Shade of the Quran – Sayyid Qutb