Sayyiduna Abu al-Darda' (may Allah be pleased with him) narrates: We were travelling with the Prophet (peace and blessings be upon him), and the Prophet (peace and blessings be upon him) said: "The mufridun have gone ahead." The people asked: "What is meant by the mufridun?" The Prophet (peace and blessings be upon him) said: "Those who keep remembering Allah, and that remembrance lifts their burdens from them (that is, by the blessing of this remembrance their troubles are removed, or their sins are forgiven), and when they come on the Day of Resurrection they will be light."
Tabarani recorded it from his teacher Abdullah bin Muhammad bin Sa'id bin Abi Maryam, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 16759