Then Allah says:

[وَلاَ تَشْتَرُواْ بِعَهْدِ اللَّهِ ثَمَناً قَلِيلاً]

(And do not use an oath by Allah for the purchase of little value.) meaning, do not neglect an oath sworn in the Name of Allah for the sake of this world and its attractions, for they are few, and even if the son of Adam were to gain this world and all that is in it, that which is with Allah is better for him, i.e., the reward of Allah is better for the one who puts his hope in Him, believes in Him, seeks Him and fulfills his oaths in the hope of that which Allah has promised. This is why Allah says:

[إِن كُنتُمْ تَعْلَمُونَمَا عِندَكُمْ يَنفَدُ]

(if you only knew. Whatever you have will be exhausted,) meaning, it will come to an end and will vanish, because it is only there for a certain, limited time.

[وَمَا عِندَ اللَّهِ بَاقٍ]

(and what is with Allah will remain.) meaning, His reward for you in Paradise will remain, without interruption or end, because it is eternal and will never change nor disappear.

[وَلَنَجْزِيَنَّ الَّذِينَ صَبَرُواْ أَجْرَهُمْ بِأَحْسَنِ مَا كَانُواْ يَعْمَلُونَ]

(And to those who are patient, We will certainly grant them their rewards in proportion to the best of what they used to do. ) Here the Lord swears, with the Lam of affirmation, that He will reward the patient for the best of their deeds, i.e., He will forgive them for their bad deeds.

[مَنْ عَمِلَ صَـلِحاً مِّن ذَكَرٍ أَوْ أُنْثَى وَهُوَ مُؤْمِنٌ فَلَنُحْيِيَنَّهُ حَيَوةً طَيِّبَةً وَلَنَجْزِيَنَّهُمْ أَجْرَهُم بِأَحْسَنِ مَا كَانُواْ يَعْمَلُونَ ]

(97. Whoever does righteous deeds - whether male or female - while he (or she) is a believer; then We will certainly give them a good life, and We will certainly grant them their rewards in proportion to the best of what they used to do.)