For those who testify the Best Book in the best manner, they have the best and more; no darkness will cover their faces, nor humiliation, such are the inmates of Paradise, they will abide in It forever.
Verses 39: 17-18 say: “And those who have avoided serving satanic forces and turned back into Allah, for them have glad tidings; so, give glad tidings to My servants, to those who listen the Best Book and follows It in the best manner, such are the ones whom Allah has guided, and such are the men of understanding”. Two conditions are specified in verses 39: 53-55 to forgive offenses altogether. The first one is turning to Lord by repenting and submitting all to him with a soul before the death arrives; and the second one is to follow the Best Book—Adhikr—in the best manner. Whoever testifies the Best Book, Lord will make all his things easy, and whoever rejects the Best Book, the Lord will make all his things difficult as explained in 4: 28 and 9: 99.
“For those who testify the Best Book in the best manner, they have the best and more “mentioned in this verse means the inhabitants of Paradise who testified Adhikr can intercede for the weakling disbelievers as told in verse 50: 35. It is told in verse 34: 23 that without Adhikr—the Permission of Lord–no intercession will be accepted, then when terror is removed from the hearts of weakling disbelievers (who were led into the Fire after Trial) after the duration of punishment, they will ask the relative believer in Paradise: "What has your Lord said?", the believer will reply: "The Truth—Adhikr". See the explanations 1: 3; 2: 127 and 3: 106.