1. ‘Abdullah ibn ‘Umar radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said:“Indeed Allah relieves difficulties for 100 neighbours due to a pious Muslim living near them”.[al-Mu’ajjam al-Kabir, Tabrani; Mu’alim, Baghawi]
2. Rasulullah sallallahu ‘alaihi wasallam said: “If it were not for those servants of Allah who offer Salah and milk drinking children and four-legged grass eaters, then surely Allah would punish you and it would be a strong punishment”.[Sunan Bayhaqi; Tabrani]
3. Sa’d bin Abi Waqqas radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said:“It is only due to your elders that you are given help and sustenance”.[Bukhari]
4. ‘Ubada radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi
5. wasallam said: “There are 30 Abdal in my ummah. It is only due to them that the world continues. It is only due to them that rainfall occurs for you and it is only due to them that you receive help”.[al-Kabir, Tabrani]
6. ‘Ali al-Murtada radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said: “There are 40 Abdal in Sham (Syria). When one dies, Allah replaces him with another. It is only because of them that rain falls and only due to them that enemies are defeated. It is because of them that punishment is waived from the people of Sham”.[Ahmad]
7. ‘Awf ibn Malik radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said: “The Abdal are in Sham. It is due to their barakah that people get help and it is only due to them that sustenance is provided”.[al-Kabir, Tabrani]
8. Anas bin Malik radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said: “The world will never cease to have at least 40 awliya (saints) who will be similar to Sayyiduna Ibrahim Khalil Allah ‘alaihis salam. It will be due to them that you will get rainfall and due to them that you shall receive help”.[al-Awsat, Tabran]
9. Abu Huraira radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said:“Thirty people who will be similar to Ibrahim ‘alaihis salam will always remain on the Earth. It is thanks to them that your pleas will be heard and due to their barakah that rainfall will happen”.[ibn Hibban fi Tarikh]
10. ‘Abdullah ibn Mas’ud radiyallahu ta’ala ‘anhu narrates that Rasulullah
11. sallallahu ‘alaihi wasallam said:“There shall always be 40 men in my ummah whose hearts will be similar to the heart of Ibrahim ‘alaihis salam. Allah will remove difficulties from the people due to them. Their title will be Abdal”.[Abu Nu’aym fi Hulya]
12. Anas radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said: “When Allah wishes to do good with a person, He uses the person to remove difficulties from the people”.[Shu’b al-Iman, Bayhaqi]
13. ‘Abdullah ibn ‘Umar radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said: “There are some people of Allah whom Allah selects so that they may remove difficulties from the creation. People in a bad state will come to them for their needs. Such people are free from the punishment of Allah”.[al-Kabir, Tabrani]
14. Anas radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said: “When Allah wishes to do good with a person, He makes the person towards whom people turn for their needs”.[Musnad al-Firdaus]
15. ‘Abdullah ibn Mas’ud radiyallahu ta’ala ‘anhu narrates that Rasulullah sallallahu ‘alaihi wasallam said: “There are 300 friends of Allah in the creation whose hearts are like that of Prophet Adam ‘alaihis salam. There are 40 whose hearts are similar to the heart of Musa ‘alaihis salam and 7 whose hearts are similar to the heart of Ibrahim ‘alaihis salam. There are 5 whose hearts are like that of Jibra’il and 3 whose hearts are like that of Mika’il and one whose heart is like the heart of Israfil. When he (whose heart is like Israfil) dies, then one of the three whose heart is like Mika’il replaces him and one of the five (whose hearts are like Jibra’il) replaces him. One of the seven replaces one of the five, one of the forty replaces one of the seven and one of the three-hundred replaces one of the forty and a normal Muslim replaces one of the three-hundred. It is due to these 356 awliya that creation are given life and killed, due to them rain falls, vegetation grows and difficulties are removed”.[Abu Nu’aym fi Hulya; ibn Asakir]

Reference: https://theahlesunnah.wordpress.com/2012/09/11/the-friends-of-allah-are-created-to-remove-difficulties-dafi-al-balaa/