It is narrated from Sayyiduna Sa'id bin al-Musayyib (may Allah have mercy on him) that a man came to him and said: "O Abu Muhammad! Shall I not tell you what we do in our battles?" He said: "Do not tell." The man said: "When the Messenger of Allah (peace and blessings be upon him) would stay in any town, he would invite the people of that town to Islam. If they accepted, he would include them among himself and his companions. If they refused, he would invite them to pay jizyah. If they paid jizyah, he would accept it. If they refused, he would declare war on equal terms. And even if the least of his companions made a covenant with anyone, all of them would fulfill it together."
Hadith Referenceسنن سعید بن منصور / كتاب الجهاد / 3652
Hadith Takhrij«أخرجه سعيد بن منصور فى «سننه» ترقيم الدرالسلفية برقم:، 2475، وعبد الرزاق فى «مصنفه» برقم: 9421، 9432»