Does the tribulation of the grave expiate a Muslim's sins or alleviate them?

God has provided the [Muslim] nation with expiations for sins before the reckoning, among them being the torment of the grave. Whatever pain afflicts a believer in this world and in the Barzakh (interim period between death and resurrection), God expiates his sins thereby, as stated in the Hadith: "No fatigue, nor illness, nor anxiety, nor sorrow, nor harm, nor distress befalls a Muslim, not even a prick of a thorn, but that Allah expiates some of his sins thereby." Likewise, the trials, compression, and terror that occur in the grave also expiate sins.