Sensing the need of the poor person and treating him kindly come under the heading of piety, for the attaining of which fasting was prescribed
Question

                Many Muslims repeat this phrase: “We fast so that we can feel for the poor.” Is there any evidence in the Qur’an or Sunnah for that?
Praise be to Allah.
	Allah does not prescribe anything but for a wise reason, 
	whether people are aware of it or it is hidden from them, or they know part 
	of it and part of it is hidden from them. Allah has great wisdom that human 
	minds cannot comprehend. 

	Allah, may He be exalted, has mentioned the wisdom behind the 
	prescription and obligation of fasting in the verse in which He says 
	(interpretation of the meaning):

	“O you who 
	believe! Observing As-Saum (the fasting) is prescribed for you as it was 
	prescribed for those before you, that you may become Al-Muttaqoon (the 
	pious)”

	[al-Baqarah 2:183]. 

	Some of the scholars have stated that one of the issues of 
	piety that fasting encourages is so that the rich person will come to 
	understand the situation of the poor person, and how he suffers from hunger 
	and need, so that this will motivate him to treat him kindly and meet his 
	brother’s needs. This is part of piety. 

	Taqwa (translated here as piety) is a general term which 
	includes doing all that is good and refraining from all that is evil. Ibn 
	Katheer (may Allah have mercy on him) said: 

	Taqwa (piety) is a general term which includes doing all acts 
	of obedience and refraining from all evils. 

	End quote from Tafseer Ibn Katheer (1/492) 

	Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: 

	Taqwa (piety) is a general term which includes doing all that 
	Allah has enjoined and refraining from all that He has forbidden, because 
	the word is derived from wiqaayah (protection); what it means is taking 
	measures to protect oneself from the punishment of Allah, and there is no 
	way to protect oneself from the punishment of Allah except by doing that 
	which He has enjoined and refraining from that which He has prohibited. 

	End quote from Majmoo‘ Fataawa wa Rasaa’il al-‘Uthaymeen 
	(24/40). 

	There is no text in the Holy Quran or in the Prophetic Sunnah 
	that specifically indicates that Allah, may He be exalted, has enjoined 
	fasting on us so that we may feel empathy with the poor. But those scholars 
	who mentioned that based it on the idea that this is included in the general 
	meaning of piety, which the Holy Qur’an states is the wisdom behind fasting, 
	and suggested that this is appropriate in the case of one who is fasting, 
	because it is known that Islamic teaching encourages helping others and 
	creating mutual love and compassion among the believers. 

	As-Sa‘di (may Allah have mercy on him) said: 

	Allah, may He be exalted, tells us of the wisdom behind the 
	prescription of fasting, as He says “that you may become Al-Muttaqoon 
	(the pious)”. Fasting is one of the greatest means of developing piety, 
	because it involves obeying the command of Allah and avoiding that which He 
	has forbidden. 

	Part of the piety that fasting involves is that the fasting 
	person refrains from that which Allah has forbidden to him of food, drink, 
	intercourse and so on, to which he is naturally inclined, seeking thereby to 
	draw closer to Allah, hoping for His reward by giving up these things. This 
	is part of piety. Piety also includes the following:

	The fasting person trains himself to remember that Allah, may 
	He be exalted, is always watching, so he gives up things that he desires 
	even though they may be available to him, because he knows that Allah is 
	watching him.

	Fasting narrows the pathways of the Shayt@ân, who flows 
	through the son of Adam like blood. Fasting weakens the Shayt@ân’s influence 
	and reduces sins.

	The fasting person usually does many acts of worship and 
	obedience, which are characteristics of piety.

	By fasting, the rich man feels the pain of hunger, which 
	makes him inclined to help the poor and destitute. This is also a 
	characteristic of piety.

	End quote from Tafseer as-Sa‘di (p. 86) 

	Shaykh Muhammad al-Mukhtaar ash-Shinqeeti (may Allah preserve 
	him) said: 

	In fasting there is much good, because it reminds the rich of 
	the poor and needy. If a person feels hunger and thirst, even though he 
	knows that at the end of the day he will be able to find food and drink, he 
	will remember the poor who do not find any food or drink, hence they said 
	that in this fast there is a great deal of good for the individual, as it 
	reminds him of the weak, especially if he is one of the rich and wealthy. 

	The rich man may forget his brethren among the weak and poor 
	because of the wealth that he has, as Allah, may He be exalted, says 
	(interpretation of the meaning):

	“Nay! Verily, 
	man does transgress all bounds (in disbelief and evil deed, etc.).

	Because he considers himself self-sufficient”

	[al-‘Alaq 96:6-7]. 

	If a person feels himself to be self-sufficient, he will 
	become arrogant, but if he feels hunger as the poor feel hunger, and he 
	feels thirst as the poor feel thirst, that will motivate him to remember 
	these weak ones and show compassion towards them. End quote. 

	Sharh Zaad al-Mustaqni‘ 
	(7/100) 

	Therefore we fast as an act of worship to Allah, may He be 
	exalted, and in obedience to Allah and His Messenger (blessings and peace of 
	Allah be upon him), so that we may attain piety and fear of Allah in our 
	hearts, which leads to happiness in both realms (this world and the 
	hereafter). And part of piety is feeling empathy for the poor, which will 
	motivate us to help them. 

	See also question no. 26862 

	And Allah knows best.