The head of the international water bureau in the Syrian ministry of irrigation keeps a host of other theological instructions on file, along with historical water agreements stretching back to 2,360 BC, via the Iraqi kingdom of Hammurabi (1792-1750 BC) and four centuries of Ottoman legislation. On Mr Musri's wall, a large map appears to show the fruits of this collected wisdom: most of Syria is coloured a dark, verdant green. But another set of files on his desk shows just how misleading maps can be.
For in the far north of his country - and it is a problem upon which Mr Musri spends almost every waking hour - the colour green is fading away. Four entire rivers, according to the Syrian ministry, have either dried up because the Turks have diverted the water courses north of the border, or been contaminated by massive pollution from Turkey. Mr Musri slides a pen down the mournful list on his desk. "The Jaljal river passes through our city of Hassake," he says. "It has dried up. "The el-Balih river virtually dried up five years ago when the Turks began using the underground water in the river's catchment area in Turkey. In summer now, the Sajar river runs out of water."
Mr Musri knows his job. He speaks fluent Turkish and two years ago completed a five-year assignment as first secretary at the Syrian embassy in Ankara. He has visited every Turkish dam on the other side of the frontier and participated in the major water resource conferences with Turkey. His pen comes to rest on another river, the Qweik, which once ran south into the great city of Aleppo. "It is no more," he says.
Not quite. When I visited the area, I found something worse. The Qweik is now a fast-flowing open sewer, its stench drifting for miles across the barren fields. In Aleppo itself, the Syrians have been forced to merge the ancient watercourse, with its underground Roman water tanks and bridges, into the city's sewerage system.
"Just 13 months ago, the Turkish side started releasing polluted water in some of our joint rivers," Mr Musri goes on. "Sewage water and drainage from the lands that carry industrial pollutants came down the al-Balih valley and we are still receiving this dirty water." And from a battered grey filing cabinet in the corner of the room comes another file, crammed with statistics of biological oxygen dissolve (BOD) measurements - a system of checking the purity of water. "In the normal course of events, there should be only 2mg BOD per litre in a river - up to 40 if it is irrigation water. But we've done 300 analyses in the al-Balih valley and they show that BOD reached 500mg per litre. This has polluted the land - it's harmed the health of our farmers and their families, and contaminated drinking water in the region."
Mr Musri, however, is a technical man. Ask him why the Turks are polluting the rivers and he replies: "It's a political question. From the technical side, we have all the information necessary to reach a joint agreement. The problem today is not so much the amount of water - though that has been a problem on the Euphrates when the Turks were filling their dams - but the quality of the water." All of which depends, it seems, on the quality of political relations between Syria and Turkey, a matter upon which Mr Musri did not wish to expand.
It is no secret, however, that Turkey's new military agreement with Israel - which allows Israeli pilots to fly in Turkish airspace along Syria's northern border - and Turkey's anger at Syrian support for Kurdish Workers' Party (PKK) separatists who are waging a brutal campaign in south-east Turkey, have brought relations between the Syrians and the Turks to their lowest point for many years. The PKK leader, Abdullah Ocalan, appears from time to time in the Syrian-controlled Lebanese Bekaa valley to issue ceasefire calls or bloodcurdling threats against his Turkish antagonists. A series of small bombs that exploded in Syrian towns last year were probably the work of Turkish government agents, and reports of sniping by Turkish soldiers across the northern border have been confirmed by a Syrian security source. At one point last year, Syrian armour was moved north after reports of Turkish troop movements. Publicly, the Syrians do not speak about the lost lands around Alexandretta - ceded by the French mandate authority in 1939 in the vain hope of persuading Turkey to join the coming Allied fight against Hitler. But they have not forgotten.
And they are ever mindful of that most ancient of rivers that flows from Turkey, the epic Euphrates whose waters slackened when Turkey built its dams to the north and are now, according to the Syrians, in danger of falling again as the Turks establish two new dams - at Biracik and Karkamish - for land irrigation. Biracik alone, Mr Musri says, is intended to irrigate 81,670 hectars of land. "This means it will reduce our share of water in the Euphrates. Syria and Iraq are ready to sign a final agreement with Turkey to share the water of the Euphrates in an equitable way according to international law. But the Turkish side, till now, has not reached final agreement because it would like to have time to finish its planned projects."
Mr Musri takes the view that existing legislation between Turkey, Syria and Iraq - especially a 1987 protocol signed by former Turkish prime minister Turgut Ozal - form the basis of a final agreement. The irony, of course, is that the sharing of waters between Syria and Iraq has long ago been agreed - even though Saddam Hussein remains a visceral enemy of President Hafez al-Assad of Syria.