on the authority of ibn 'abbaas (radiallaahu anhumaa) that the messenger of allaah (sallallaahu alayhi wa sallam) said :

a hasan hadeeth related by ibn maajah, and al-bayhaqee and others.

explanation of hadeeth number 39

and it has been related in the tafseer of the statement of allaah, 'azza wa jall, "and whether you disclose what is in your ownselves or conceal it, allaah will call you to account for it" [soorah al-baqarah, 284] that when this aayah was revealed it became a great burden upon the sahaabah, radiallaahu anhum. so abu bakr, 'umar 'abd-ur-rahmaan bin 'awf and mu'aadh bin jabal, amongst a number of others, came to the messenger of allaah (sallallaahu alayhi wa sallam) and said "we have been burdened with actions which we find we are incapable of sustaining. verily one of us may mention to himself [evil] things which he would not like to settle in his heart, even if he were to be offered the wealth of the dunyaa for doing so." so the prophet (sallallaahu alayhi wa sallam) said "i fear that you are saying what the banoo israa'eel said : 'we hear and we disobey'. but, rather, you should say : 'we hear and we obey'". so this became very hard upon them, and they remained in this state for some time. then allaah ta'aalaa revealed upon them his mercy and that which gave them respite, with his statement :

so allaah 'azza wa jall said, in a hadeeth qudsee, "i have decreed so", and thus allaah revealed to the muslims that which lightened their burden, and which abrogated the aayah which came before it.

al-bayhaqee said that imaam ash-shaafi'ee, rahimahu allaah, said :
allaah subhaanahu said "except him who is forced [to kufr] and whose heart is at rest with faith" [soorah an-nahl, 106], and so there are rulings regarding kufr. and since allaah has dropped the ruling of kufr from the one who is forced to utter such words, then similarly must be the case of the one who is mistaken or the one who forgets, since when the greater of two issues is dropped, then that which is less than it is also dropped along with it. further, it is related from ibn 'abbaas (radiallaahu anhumaa) from the messenger of allaah (sallallaahu alayhi wa sallam) "verily allaah has pardoned for me my ummah : their mistakes, their forgetfulness, and that which they have been forced to do under duress", and it has been related from 'ayeshah (radiallaahu anhaa) from the prophet (sallallaahu alayhi wa sallam) that he said : "there is no divorce nor freeing of a slave in a state of anger", and this is the madhhab of 'umar and abdullaah ibn 'umar and 'abdullaah ibn az-zubair (radiallaahu anhum). and thaabit bin al-ahnaf married the mother of a son of 'abd-ur-rahmaan bin zayd bin al-khattaab, so 'abd-ur-rahmaan intimidated and threatened him with a whip, until he unwillingly divorced her, during the khilaafah of 'abdullaah bin az-zubair. so abdullaah ibn 'umar said to him that the divorce was not valid, as it had been made under duress, and so he should return to her. at that time abdullaah bin az-zubair, the khaleefah, was in makkah so he [ibn az-zubair] wrote to his governor in madeenah to return thaabit's wife to him, and to punish 'abd-ur-rahmaan bin zayd. so safiyyah bint abee 'ubayd, the wife of 'abdullaah bin 'umar, prepared her for her return, and 'abdullaah bin 'umar attended their wedding feast.

and allaah knows best.

summary :

• that allaah has forgiven muslims for the sins that they commit by mistake
• that allaah has forgiven muslims for what they do out of forgetfulness
• that allaah has forgiven muslims for what they are compelled to do against their wishes
• that we are to overlook and forgive each other for what we do by mistake, or out of forgetfulness or under duress, since allaah himself does so