Ibn Rajab al-Hanbali writes in the conclusion of his discussion of the last ten days of Ramadan:
إخواني ! المعوّل على القبول لا على الاجتهاد ، والاعتبار ببر القلوب لا بعمل الأبدان .ربُّ قائم حظه من قيامه السهر ؛ كم من قائم محروم ، ومن نائم مرحوم ؛ هذا نام وقلبه ذاكر ، وهذا قام وقلبه فاجر .
O my brothers! The final determination [of deeds] depends on the acceptance and not on striving, and the account is according to the birr (righteousness) of the heart and not according to physical actions. Perhaps the one who stands the night in prayer has only gained sleeplessness – for how many of those who stand are deprived [of Allah’s mercy] and how many of those who sleep are given mercy. This one sleeps while his heart is attendant [to his Lord], and this one stands while his heart is immoral.
إن المقادير إذا ساعدت ***** ألحقت النائم بالقائم
Verily the measurement for one of ultimate blessing;
he is joined with those who stand in prayer even while he is sleeping
لكن العبد مأمور بالسعي في اكتساب الخيرات والاجتهاد في الاعمال الصالحات ؛ وكل مَيَسّرٌ لما خلق له . أما أهل السعادة فييسرون لعمل أهل السعادة ، وأما أهل الشقاوة فييسرون لعمل أهل الشقاوة . < فَأَمَّا مَنْ أَعْطَىٰ وَاتَّقَىٰ * وَصَدَّقَ بِالْحُسْنَىٰ * فَسَنُيَسِّرُهُ لِلْيُسْرَىٰ * وَأَمَّا مَن بَخِلَ وَاسْتَغْنَىٰ * وَكَذَّبَ بِالْحُسْنَىٰ * فَسَنُيَسِّرُهُ لِلْعُسْرَىٰ > فالمبادرة المبادرة إلى اغتنام العمل فيما بقي من الشهر ، فعسى أن يستدرك به ما فات من ضياع العمر
However, the slave is commanded to hasten in earning good deeds and exerting himself in righteous good works. And each person is facilitated towards that for which they were created. As for those people of ultimate prosperity, then they are facilitated to perform the actions of the people of ultimate happiness. And as for the people of ultimate anguish, then they are facilitated to perform the actions of the people of ultimate anguish:
فَأَمَّا مَنْ أَعْطَىٰ وَاتَّقَىٰ * وَصَدَّقَ بِالْحُسْنَىٰ * فَسَنُيَسِّرُهُ لِلْيُسْرَىٰ * وَأَمَّا مَن بَخِلَ وَاسْتَغْنَىٰ * وَكَذَّبَ بِالْحُسْنَىٰ * فَسَنُيَسِّرُهُ لِلْعُسْرَىٰ
“As for he who gives and has taqwa * And believes in the best [reward], * We will facilitate him toward ease. * But as for he who withholds and considers himself free of need * And denies the best [reward], * We will facilitate him toward difficulty” [92:5-10]
So the appropriate undertaking is that of seeking to amass great rewards for one’s deeds in what remains of this month, for perhaps he will achieve thereby what he has missed from his life up until this point.
[Lataa’if al-Ma’aarif pg. 351]