وَإِذَا سَأَلَكَ عِبَادِى عَنِّى فَإِنِّى قَرِيبٌ ۖ أُجِيبُ دَعْوَةَ ٱلدَّاعِ إِذَا دَعَانِ ۖ فَلْيَسْتَجِيبُوا لِى وَلْيُؤْمِنُوا بِى لَعَلَّهُمْ يَرْشُدُونَ

Fasting by its very nature is an act of patience, and patience involves putting up with all kinds of difficulties in order to carry out God’s commandments. This helps man to attain that state of mind which brings him closer to God. Only those find God who surrender themselves totally to Him, only the words of those reach God whose ‘wavelength’ matches that of God. The command to fast is followed by the command, ‘Do not consume one another’s property by unjust means’ (see 2. 188 ). This shows the essence of fasting. The real aim of fasting is to create such a feeling of subservience that when God commands us to abstain from anything, we must do so forthwith. The lesson fasting gives us is that even if God wants us to stay away from lawful things, we must show no hesitation in obeying His command. Thus one who abstains from lawful things if God wants him to do so, will have no difficulty in abstaining from unlawful things if God so commands.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (2:186)