If a course has no fixed time, give it one. Write down which day and which hour you will watch it, put that in the calendar as though somebody else set it, and tell one person.

البقرة

يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓاْ إِذَا تَدَايَنتُم بِدَيۡنٍ إِلَىٰٓ أَجَلࣲ مُّسَمࣰّ ى فَٱكۡتُبُوهُۚ وَلۡيَكۡتُب بَّيۡنَكُمۡ كَاتِبُۢ بِٱلۡعَدۡلِۚ وَلَا يَأۡبَ كَاتِبٌ أَن يَكۡتُبَ كَمَا عَلَّمَهُ ٱللَّهُۚ فَلۡيَكۡتُبۡ وَلۡيُمۡلِلِ ٱلَّذِي عَلَيۡهِ ٱلۡحَقُّ وَلۡيَتَّقِ ٱللَّهَ رَبَّهُۥ وَلَا يَبۡخَسۡ مِنۡهُ شَيۡـࣰٔ اۚ فَإِن كَانَ ٱلَّذِي عَلَيۡهِ ٱلۡحَقُّ سَفِيهًا أَوۡ ضَعِيفًا أَوۡ لَا يَسۡتَطِيعُ أَن يُمِلَّ هُوَ فَلۡيُمۡلِلۡ وَلِيُّهُۥ بِٱلۡعَدۡلِۚ وَٱسۡتَشۡهِدُواْ شَهِيدَيۡنِ مِن رِّجَالِكُمۡۖ فَإِن لَّمۡ يَكُونَا رَجُلَيۡنِ فَرَجُلࣱ وَٱمۡرَأَتَانِ مِمَّن تَرۡضَوۡنَ مِنَ ٱلشُّهَدَآءِ أَن تَضِلَّ إِحۡدَىٰهُمَا فَتُذَكِّرَ إِحۡدَىٰهُمَا ٱلۡأُخۡرَىٰۚ وَلَا يَأۡبَ ٱلشُّهَدَآءُ إِذَا مَا دُعُواْۚ وَلَا تَسۡـَٔمُوٓاْ أَن تَكۡتُبُوهُ صَغِيرًا أَوۡ كَبِيرًا إِلَىٰٓ أَجَلِهِۦۚ ذَٰلِكُمۡ أَقۡسَطُ عِندَ ٱللَّهِ وَأَقۡوَمُ لِلشَّهَٰدَةِ وَأَدۡنَىٰٓ أَلَّا تَرۡتَابُوٓاْ إِلَّآ أَن تَكُونَ تِجَٰرَةً حَاضِرَةࣰ تُدِيرُونَهَا بَيۡنَكُمۡ فَلَيۡسَ عَلَيۡكُمۡ جُنَاحٌ أَلَّا تَكۡتُبُوهَاۗ وَأَشۡهِدُوٓاْ إِذَا تَبَايَعۡتُمۡۚ وَلَا يُضَآرَّ كَاتِبࣱ وَلَا شَهِيدࣱۚ وَإِن تَفۡعَلُواْ فَإِنَّهُۥ فُسُوقُۢ بِكُمۡۗ وَٱتَّقُواْ ٱللَّهَۖ وَيُعَلِّمُكُمُ ٱللَّهُۗ وَٱللَّهُ بِكُلِّ شَيۡءٍ عَلِيمࣱ‏

You who believe, when you contract a debt for a stated term, put it down in writing: have a scribe write it down justly between you. No scribe should refuse to write: let him write as God has taught him, let the debtor dictate, and let him fear God, his Lord, and not diminish [the debt] at all. If the debtor is feeble-minded, weak, or unable to dictate, then let his guardian dictate justly. Call in two men as witnesses. If two men are not there, then call one man and two women out of those you approve as witnesses, so that if one of the two women should forget the other can remind her. Let the witnesses not refuse when they are summoned. Do not disdain to write the debt down, be it small or large, along with the time it falls due: this way is more equitable in God’s eyes, more reliable as testimony, and more likely to prevent doubts arising between you. But if the merchandise is there and you hand it over, there is no blame on you if you do not write it down. Have witnesses present whenever you trade with one another, and let no harm be done to either scribe or witness, for if you did cause them harm, it would be a crime on your part. Be mindful of God, and He will teach you: He has full knowledge of everything

Qur’an 2:282read it in the library