Qur'an
Surah 2 2:265
وَمَثَلُ ٱلَّذِینَ یُنفِقُونَ أَمۡوَ ٰلَهُمُ ٱبۡتِغَاۤءَ مَرۡضَاتِ ٱللَّهِ وَتَثۡبِیتࣰا مِّنۡ أَنفُسِهِمۡ كَمَثَلِ جَنَّةِۭ بِرَبۡوَةٍ أَصَابَهَا وَابِلࣱ فَءَاتَتۡ أُكُلَهَا ضِعۡفَیۡنِ فَإِن لَّمۡ یُصِبۡهَا وَابِلࣱ فَطَلࣱّۗ وَٱللَّهُ بِمَا تَعۡمَلُونَ بَصِیرٌ ۝٢٦٥
But those who spend their wealth in order to gain God’s approval, and as an affirmation of their own faith, are like a garden on a hill: heavy rain falls and it produces double its normal yield; even if no heavy rain falls, it will still be watered by the dew. God sees all that you do

وَتَثْبِيتًا مِّنْ أَنفُسِهِمْ
(while they in their own selves are sure and certain) meaning, they are certain that Allah shall reward them for these righteous acts with the best rewards. Similarly, in a Hadith collected by Al-Bukhari and Muslim, the Messenger of Allah ﷺ said,
«مَنْ صَامَ رَمَضَانَ إِيمَانًا وَاحْتِسَابًا»
(Whoever fasts Ramadan with faith and expectation...) meaning, believing that Allah commanded the fast, all the while awaiting His reward for fasting it.
Allah's statement,
كَمَثَلِ جَنَّةٍ بِرَبْوَةٍ
(is that of a garden on a Rabwah) means, the example of a garden on `a height above the ground', as the majority of scholars have stated. Ibn `Abbas and Ad-Dahhak added that it also has flowing rivers.
Allah's statement,
أَصَابَهَا وَابِلٌ
(Wabil falls on it) means, heavy rain as we stated, So it produces its,
أُكُلُهَا
(yield of harvest) meaning, fruits or produce,
ضِعْفَيْنِ
(doubles), as compared to other gardens.
فَإِن لَّمْ يُصِبْهَا وَابِلٌ فَطَلٌّ
(And if it does not receive Wabil, a Tall suffices it.)
Ad-Dahhak said that the `Tall' is light rain. The Ayah indicates that the garden on the Rabwah is always fertile, for if heavy rain does not fall on it, light rain will suffice for it. Such is the case regarding the believer's good deeds, for they never become barren. Rather, Allah accepts the believer's righteous deeds and increases them, each according to his deeds. This is why Allah said next,
وَاللَّهُ بِمَا تَعْمَلُونَ بَصِيرٌ
(And Allah is All-Seer of what you do) meaning, none of His servants' deeds ever escapes His perfect watch.

(And the likeness of those who spend their wealth) the likeness of the wealth of those who spend it (in search of Allah's pleasure) seeking Allah's pleasure, (and for the strengthening of their souls) truly, out of conviction and certitude in their hearts that they will be rewarded, (is as the likeness of a garden on a height) on an elevated plain. (The rainstorm smiteth it and it bringeth forth its fruit twofold. And if the rainstorm smite it not, then the shower) this is like the spending of the believer, whether small or great, when it is done with sincerity and fearingness, Allah multiplies it as He multiplies the fruits of a garden. (Allah is Seer of what ye do) of what you spend.

EN

But the likeness of the expenditure of those who expend their wealth seeking God’s good pleasure and to confirm themselves that is to realise the reward thereof in contrast to the hypocrites who do not hope for it since they do not believe in it is as the likeness of a garden an orchard upon a hill read rabwa or rubwa a high ground; a torrent smites it and it yields gives forth its produce read ukulahā or uklahā its fruits twofold twice the fruits of another garden; if no torrent smites it then dew tall a light drizzle which falls on it and suffices it on account of its altitude. In other words it grows and bears fruit regardless of how much rain falls; likewise are the expenditures of those mentioned they will increase with God regardless of how much they were; and God sees what you do and He will requite you for it.

EN

In verse 265, the fifth under discussion, the acts of charity which are acceptable in the sight of Allah Almighty as valid spendings, have been illustrated with an example. It is said that those who spend in the way of Allah, solely and sincerely, to seek nothing but His pleasure, and thus fortify their selves with steadfastness, are in a situation where there is a fruit farm located on some mound, then it is hit by heavy rains, then it brings forth double of its usual yield. And should it be that the rain is not that heavy, a light drizzle would become sufficient for it and Allah Almighty sees and knows what you do.
Here the merits of spending in the way of Allah, surely with sincerity of intention, and obedience to conditions set, has been made clear through this similitude. The message is: Spending with good intention and sincerity, even if it be just a little, becomes enough and helps one receive the gains of the Hereafter.

EN

If an individual has some goal in mind, his own striving towards the attainment of that goal further strengthens his will-power and increases the mental resolve which enables him to reach his objective. Should it be the objects of his own desires towards which his efforts are directed, then the more he exerts himself, the more he will set his heart on them. However, should it be the will of God that holds pride of place in determining his actions, then it will be God on whom his heart is set. One acts at all events under conditions which are sometimes difficult and sometimes comparatively easy. But the more difficult the conditions one encounters, the greater will be the increase in one’s will-power and the stronger one’s connection to that on which one’s heart is set. One who spends for the cause of God under normal conditions will certainly have his reward from God. However, when spending for God’s cause is done in adverse circumstances, which call for a special exercise of will-power, the reward which God grants on such occasions will be commensurately greater. For instance, if the outlay of one’s wealth is done on something from which no worldly benefit will be forthcoming, then in that case it is done solely for the sake of God. Then one may have to give to a person to whom one would rather not give anything. Again it is done just to please God. One may have a grudge against someone, yet one still extends to him the hand of friendship. All these acts strengthen one’s bond with the Lord, opening the way to His special grace and succour.