from Chachnama : when one of the raiding expeditions sent by the Caliphate in Iraq under Bazil was defeated by the Sindhis, and the commander fell in battle, [this was before Qasim's successful expedition]
It is related on the authority of Abdurrahmán son of Abdríh, that when Bazíl was killed, the people of Nerún became restless with the fear that the Arab army, bound as it was to take revenge, would, when passing by Nerún, swoop down on them and destroy them. At that time a Samani was the governor of Nerún. (The Samani was frightened) for he sent men in his confidence to Hajjáj to seek his pardon for what had happened, and he fixed a tribute on himself, and undertook to send it regularly. Hajjáj, the governor of the Khalífah sent a letter of pardon, and cheered him with solemn promises. (But) “You must,” said he, “release all the prisoners, or else I will not leave a single infidel up to the limits of China, and will make them all a prey to the sword of Islám.”
When Hajjáj determined to appoint another agent for Hind, Amir son of Abdulláh applied for the post and Hajjáj said to him: “You covet the place, but the astrologers have found out after consulting their books, and I too have learnt in my own way, by throwing dice, that the country of Hind will be conquered by Ámir Imadud-dín Muhammad Kásim son of Ukail Sakifí.”
Note that astrology and more importantly "dice" which was roundly denounced as "gambling" - was apparently okay in the early years of Islam. A previous reference to Samani connects the term firmly with "Budhruk/Buddharakshita" -a monk, and hence in general refers to a ranking "Buddhist", with monastic connections or posts. [Samani - Sraman. Here Jaina connections can be ruled out from contextual refs]
Here is how they help out Qasim:
When Muhammad Kásim left Debal he went straight to the fortified town of Nerún which was about 25 leagues from Debal.
Muhammad Kásim sends his confidential men to Nerún.
The people of Nerún now closed the gates of the fort. The Samaní, who was the ruler of the place and headman of the people, had gone to Dáhar, and Muhammad Kásim became very anxious owing to the paucity of provisions for the army, especially of forage for animals. But, after 5 or 6 days, when the Samaní returned, he sent two leading men with a letter from Hajjáj. He also sent provisions for men and horses to the Arab camp. Through those two men, he sent verbal messages to the Arab General, saying:—“I myself and all my men are subjects of the Khalífah, and we hold this place subject to the command and in accordance with the terms of the letter of Hajjáj. In fact we owe our permanent position to his help and patronage and encouragement, but as I was absent, the people became afraid and closed the gates.” Then the Samaní opened the gates of the fort, and the natives began to make bargains and have dealings with the soldiers. Muhammad Kásim was thereupon so much pleased that he wrote a letter to Hajjáj, acknowledging, with thanks, the services rendered by the Samaní and informing him of the faithfulness and friendship of the people of Nerún.
The Samaní comes to Muhammad Kásim with provisions and presents.
Then Muhammad Kásim sent some trustworthy men out of his nobles and chiefs to the fort of Nerún with the following message:— “At first we were much annoyed to see the gates of the fort closed against us, but, on hearing the explanation of the ruler's absence, our anger subsided, and every kindness and favour was shown to you. It behoves the head of the town, Bhandarkan Samaní,* to take heart of grace and muster courage to come to us so that we may try our best to patronise him and bestow fresh favours upon him.”
An account of the conquest of Síwistán and some other places attached to it and the taking of the fort.
The next day when the true dawn appeared from behind the dark curtain (of the sky) with a cloak of ash-coloured satin, the Samaní came to the presence of Muhammmad Kásim with many presents and plentiful offerings, and obtained an honourable reception. To entertain Muhammad Kásim as a distinguished guest, he supplied him with provisions to such an extent that the soldiers got sufficient corn for their needs. Muhammad Kásim then appointed a representative within the fort. He (also) built a mosque in the place of the idol-temple of Budh, and appointed a erier to call the people to prayer, and a priest (Imám) to be their guide in prayers and other religious matters. After some days, he resolved to go to Síwistán.* That fortified town is to the west of the Mehrán on the top of a hill. Muhammad Kásim entertained hopes that the whole of that country would be conquered by the Musalmans. After that end was attained in regard to the country of Síwistán, he thought of returning thence and arranging to cross the river, in order to proceed against Dáhar. He prayed to the great and glorious God to give enlightened reason and right thought to the people of Arabia for their guidance, and to make it possible for them to fight successfully against the infidels.
War with the people of Síwistán.
When Muhammad Kásim had completely settled the affairs at Nerún, he prepared to go to Síwistán, and he, accompanied by the Samaní, started for that place. He travelled, stage by stage, till he arrived at a town called Maój, about 30 leagues from Nerún.* In that town, there was a Samaní, who was a chief among the people. The ruler of that fortified town was a cousin of Dáhar Chach, by name Bachehrá son of Chandar. On the approach of the Arabs, the Samaní party assembled, and sent a message to Bachehrá, saying:—“We people are a priestly class (Násiks), our religion is peace and our creed is good will (to all). According to our faith, fighting and slaughtering are not allowable. We will never be in favour of shedding blood. You are sitting quite safe in a lofty palace; we are afraid that this horde will come and, taking us to be your followers and dependents, will deprive us of our life and property. We have come to know that Amír Hajjáj has, under the order of the Khalífah, instructed them to grant pardon to those who ask for it. So when an opportunity offers, and when we consider it expedient, we shall enter into a solemn treaty and binding covenant with them. The Arabs are said to be faithful* to their word. Whatever they say they act up to and do not deviate from.” Bachehrá refused to accept this advice, and paid no attention to what they said. Then, Muhammad Kásim sent a spy to gather information as to the inclinations of these men, whether they were all unanimous or whether there was a difference of opinion among them. As some of the residents of the fortified town were ready to fight, and, with that intention, had issued out of the town, Muhammad Kásim encamped on the sand-hills near the gate of the town,* since there was no other open field for a battle and there was a flood of rain-water all around, and to the north the river of Sind was flowing.
Note that residents of this town were not unanimous supporters of Qasim. Note that the speech ascribed to Samani's is timeless. Exactly same arguments are heard even now. Note also that Nirun is a walled, fortified city which is controlled by a "Samani" who goes to meet "Dahir". If he is already part of a tributary chiefdom owing allegiance to the Caliphate, he could not have gone to meet an enemy of his overlord at a time when his overlord's army had already attacked Deval and conquered and looted and massacred and enslaved its population.