And indeed his effort will be seen.
As explained in verses 17: 13-14, on the Day of Judgement, the reckoning of everyone will be done by reading himself the book of deeds fastened around everyone’s neck. So, the only way to get forgiveness for the sins and offences happened before, one should read Adhikr from the first to last and should identify the sins and offences, and should confess them to Lord Allah who knows the status of chests, and should seek forgiveness for them to Lord and should propagate Adhikr among the entire mankind for not to happen sins and offences in them, as well as for utilising It as the Shield and Safeguard against all calamities, disasters, diseases and Hellfire. See explanation 25: 68-70; 39: 69-75; and 45: 28-29.