﴿He will rectify for you your deeds﴾ means by admitting you into righteous deeds while you do not know what is appropriate regarding their manner. He will enlighten you about them gradually and will grant you success in acting upon what He has made clear to you until you are upon the most complete, greatest, most pleasing, and most upright way, by the blessing of your truthful words in the good and beautiful manner.

And since man, even if he strives, is deficient, he said, indicating this so that he does not cease to acknowledge his inability: ﴿And He will forgive you your sins﴾ means He will erase them in essence and effect, so He will not punish for them nor rebuke. And since it might be thought that this is specific to those who believe, and that renewing faith is of no benefit, He removed this misconception by saying: ﴿And whoever obeys Allah﴾ meaning the one who is not greater than Him ﴿and His Messenger﴾ meaning whose greatness is from His greatness by renewing obedience with faith and its fruits at all times, so he will be fulfilling the trust to its people. ﴿Then indeed, he has succeeded﴾ and He emphasized that by saying: ﴿A great success﴾ meaning achieving all of his desires in this world and the Hereafter.