Surah 94. Ash-Sharh, Ayah 3

I.e., "the burden of thy past sins, which are now forgiven" (Tabari, on the authority of Mujahid, Qatadah, Ad-Dahhak and Ibn Zayd). In the case of Muhammad, this relates apparently to mistakes commited before his call to prophethood (ibid.), and is obviously an echo of 93:7 - 'Has He not found thee lost on thy way, and guided thee?"