يَا طُلَّابَ الْعِلْمِ، احْفَظُوا الْكُتُبَ وَلَا تُهْمِلُوا أَوْرَاقَهَا.
Students of knowledge, protect the books and do not neglect their leaves.
وَإِذَا أَرَدْتُمْ نَقْلَهَا فَاسْتَأْذِنُوا الْمَسْؤُولَ.
If you intend to move them, ask the responsible person for permission.
فَحِفْظُ الْكِتَابِ حِفْظٌ لِلْمَعْرِفَةِ.
For safeguarding a book is safeguarding knowledge.
This speech seeks to regulate conduct, so commands, prohibitions and conditional instructions replace the past-tense report. It ends with a general reason for compliance. A single topic thus requires different forms when the hearer and communicative purpose change.