Sayyiduna Ubadah bin Samit (may Allah be pleased with him) said: I asked: O Messenger of Allah! What is the meaning of Allah’s statement «لَهُمُالْبُشْرَىفِيالْحَيَاةِالدُّنْيَا» that is, “for them are glad tidings in the life of this world and in the Hereafter”? The Prophet (peace and blessings be upon him) said: “You have asked about something that no one before you has asked, nor has anyone from my Ummah.” He said: “It means a good dream which a Muslim sees himself or which someone else sees for him.”
Hadith Referenceسنن دارمي / من كتاب الرويا / 2173
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده صحيح إذا كان أبو سلمة سمعه من عبادة قال ابن خراش: لم يسمع أبو سلمة من عبادة بن الصامت، [مكتبه الشامله نمبر: 2182]
In the era of Prophethood, knowledge of the unseen and matters beyond perception would be known through divine revelation (wahy). After the Seal of the Prophets, Muhammad, the Messenger of Allah (sallallahu alayhi wa sallam), no prophet will come until the Day of Judgment. Now, it is the dreams of righteous believers through which Allah, the Exalted, grants awareness to His pious servants. And the dreams of a person who is truly trustworthy are also true; the dreams of deceitful and dishonest people are not to be relied upon. Similarly, dreams that result from indigestion or evil thoughts also hold no credibility.