The Chachnāma (Fatḥnāma-yi Sind) 31.2.6

31.2.6

Let him not depart disrespectfully, and let him have plain answers to his questions. Let not his error or hypocrisy deceive you. Always encourage your messenger and envoy by giving him fair promises, and telling him that the whole army of Islam regards him as their leader or forerunner, and depends upon what he utters, and so he must deliver his message honestly and carefully. The messenger of the Musalmans should be a man of pure faith, who should speak fearlessly and faultlessly and invite and induce the infidels to accept the true creed, and belief in the unity of God. Whoever turns to the unity of God and submits to you, let him have back his property and wealth and estate; and whoever does not submit to Islam, treat him harshly and cause injury to him till he submits. Again, if any person, having once submitted to you, withdraws himself from your allegiance, you must make him understand that, as he has taken out his head from the yoke of submission he must be ready for an onslaught. Do not allow (the enemy) to cross the Mehran at their will. Tell them that if they would come over to your side of the river they would not be checked, and that you, having come from a very long distance, have the right to cross the river freely and without any hindrance and confront them in battle. Make such arrangements that there may be no doubt or misunderstanding, on this point, between the two parties.