It is narrated from Hazrat Wa'il (may Allah be pleased with him) that I prayed with the Noble Prophet (peace and blessings be upon him). During the prayer, a man said: "Alhamdulillah kathiran tayyiban mubarakan fihi." After completing the prayer, the Noble Prophet (peace and blessings be upon him) asked, "Who said these words?" That man said, "O Messenger of Allah! I said them, and I only intended good by saying them." The Noble Prophet (peace and blessings be upon him) said, "For these words, the gates of the heavens were opened, and nothing prevented them from reaching the Throne."
Hadith Referenceمسند احمد / تتمہ مُسْنَدِ الْكُوفِيِّينَ / 18860
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد ضعيف لانقطاعه، عبدالجبار بن وائل لم يسمع من أبيه