Sayyiduna Abu Hurayrah (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "The Muslim has six rights over the Muslim." It was said: "O Messenger of Allah (peace and blessings be upon him), what are they?" He said: "When you meet him, greet him with salam; when he invites you, accept his invitation; when he seeks your sincere counsel, give him sincere counsel; when he sneezes and praises Allah, respond to him; when he falls ill, visit him; and when he dies, attend his funeral prayer."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10909
Sayyiduna Jabir (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Leave people to their affairs; Allah gives some of them provision through others. And when your brother seeks sincere counsel, let him be given sincere counsel."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10910
Salim al-Makki (may Allah have mercy on him) says that a Bedouin narrated: In the time of the Prophet (peace and blessings be upon him) I brought a milch animal of mine (to Madinah) and came to Talhah bin Ubaydullah (may Allah be pleased with him), and I said: I have no knowledge of this market; if only you would sell it for me. So Sayyiduna Talhah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) forbade "that a town-dweller should sell for a desert-dweller." But go to the market, and whoever wants to buy from you, consult me, so that I tell you to sell or forbid you.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10911