Sayyiduna Abu al-Darda' (may Allah be pleased with him) reports this saying of the Prophet (peace and blessings be upon him): "If you knew what I know, you would laugh little and weep much, and you would go out to the wastelands to cry out humbly before Allah. You do not know whether you will be saved or will not be saved."
Al-Tabarani recorded it, and al-Bazzar recorded something similar via the daughter of Sayyiduna Abu al-Darda' (may Allah be pleased with him) from her father, and I do not know this daughter; the rest of al-Tabarani's narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الزهد / 17706