إِلَّا الَّذينَ آمَنوا وَعَمِلُوا الصّالِحاتِ فَلَهُم أَجرٌ غَيرُ مَمنونٍ

Except those who have faith and do righteous deeds. There will be an everlasting reward for them.

EXEGESIS

Īmān literally means approval, confirmation, admittance, and attestation.^{‎[1]Tibyan, 1/55.}

Ṣāliḥāt is an adjective for an omitted noun which is aʿmāl (deeds), and this is known because of the context. Such a contraction is used almost everywhere in the Quran because it forms a beautiful ellipsis. Ṣāliḥāt is a plural active participle from the root ṣ-l-ḥ, which indicates competence, appropriateness, and righteousness. A comprehensive discussion on the meaning of faith (īmān) and righteous deeds (ṣāliḥāt) can be found in the exegesis of 103:3.

Mamnūn is a past participle derived from the root m-n-n which in the context of this verse means to cut off.^{‎[2]Lisan, under m-n-n.} The bounties given to the righteous is negated to be cut off by the preposition ghayr. This means that those who have faith and do righteous deeds will benefit from the everlasting and flawless bounties and rewards of God. 

EXPOSITION

In this verse God makes an exception for the descent into the lowest of the low for those who have faith and do righteous deeds stating that they will benefit from the everlasting^{‎[3]Mizan, 20/542.} reward of God which is free from any deficiency.^{‎[4]Nemuneh, 27/154; Tabrisi, 10/776.}

Some exegetes^{‎[5]Tabrisi, 10/776.} maintain that faith in this verse refers to having faith in God only, whilst others^{‎[6]Nemuneh, 27/154; Mizan, 20/542.} have chosen a wider meaning of faith which includes faith in God as well as the prophets and messengers, the hereafter, angels, and so forth. A comprehensive discussion on this can be found in 103:3.

In reality, a sound belief system is that which gives direction to the actions of an individual. There are three main dimensions in having faith and doing righteous deeds which must be considered. First is the intention and the motive of the agent which needs to be pure and sincere and having a sound faith provides that. Second is assessing and understanding the result of the actions the agent is performing, whether they produce good results or are in vain. Third is to consider the quality by which the deeds are performed and ensuring that the agent does not ruin their intention or action by deviating from the original path.^{‎[7]Tafsīr al-Bayān.}

Finally, an individual who has such a faith and does righteous deeds will benefit from the eternal reward of God which is free from any sort of deficiency. This can only be achieved in the next life, since in this world even the greatest reward one achieves is temporary and there is always more which can be desired.

[1] Tibyan, 1/55.
[2] Lisan, under m-n-n.
[3] Mizan, 20/542.
[4] Nemuneh, 27/154; Tabrisi, 10/776.
[5] Tabrisi, 10/776.
[6] Nemuneh, 27/154; Mizan, 20/542.
[7] Tafsīr al-Bayān.