Have an intention of fasting from the night before if you wish to fast during the day; strive for sincerity in your acts of worship; ensure your intentions are pure when performing them .

This hadith, narrated by Ibn 'Umar, teaches us that fasting is an act of worship that should be done with intention and willingness. It is important to have the intention of fasting from the night before in order for it to be accepted as a valid form of worship. If one does not have this intention, then they are not obligated to fast and abstain from food and drink during the day. This hadith also teaches us that we should always strive for sincerity in our acts of worship and ensure that our intentions are pure when performing them.