The recompense of one who spreads the evil deeds of his believing brother and seeks after his faults – Imam Ibn Rajab
The recompense of one who spreads the evil deeds of his believing brother and seeks after his faults and exposes his defects, is that Allaah will seek after his faults and disgrace him (by exposing them) even if he may have committed them in the privacy of his own home.
This is based on what has been reported from the Prophet صلى الله عليه وسلم in several places, and Imaam Ahmad, Abu Dawood and At-Tirmidhee have transmitted it from numerous paths of narration. 
At-Tirmidhee transmitted from the hadeeth of Waa’ilah Ibn Al-Asqa’ on the Prophet صلى الله عليه وسلم that he said:
“Do not express joy at your brother’s misfortune or else Allaah will pardon him for it and test you with it.” 
And he (At-Tirmidhee) said that it was a hasan ghareeb hadeeth. He also reports the hadeeth of Mu’aadh ” in marfoo’ form: “Whoever condemns his brother because of a sin (he committed) will not die until he commits it (himself).” Its chain of narration is munqati’ (broken).
Al-Hasan (Al-Basree) said: “It used to be said: ‘Whoever condemns his brother for a sin that he repented from, will not die until Allaah tests him with it (i.e. the same sin).’” 
And it is reported from the hadeeth of Ibn Mas’ood ” with a chain of narration that has weakness in it: “Affliction is charged by speech. So if a man condemns another man by saying that he breast-fed from a female dog, then that man (who said that) will indeed breast-feed from one.” 
The meaning of this has been reported on a group amongst the Salaf. And when Ibn Sireen failed to return a debt he owed and was detained because of it, he said: “Indeed, I am aware of the sin (I committed) by which this befell me. I condemned a man forty years ago saying to him: ‘O bankrupt one.’”
 The checking for this has been stated previously
“O you group of people that believe with your tongues but not with your hearts! Do not abuse the Muslims nor seek after their faults. For indeed, he who seeks after their faults, Allaah will seek after his faults. And whoever has Allaah seek after his faults, He will expose them, even if he may have committed them in the privacy of his own home.”
Reported by Abu Ya’laa in his Musnad (1675) and Abu Nu’aim in Ad-Dalaa’il (356) on the authority of Al-Baraa’ radhi Allaahu anhu. Al-Haithamee (rahimahullaah) said in Al-Majma’ (8/93): “Abu Laylaa reported it and its narrators are all reliable. It has also been reported from the hadeeth of Abu Barzah radhi Allaahu anhu with a strong chain of narration in Ahmad (4/421 & 424) and Abu Dawood (4880).” And in this section occurs the hadeeth of Ibn ‘Umar with a hasan chain of narration in At-Tirmidhee (2033), Al-Baghawee (3526) and Ibn Hibbaan (1494 of the Mawaarid). See also At-Targheeb wat-Tarheeb (3/177) of Al-Mundhiree.
 At-Tirmidhee reported it under number (2507) and in its chain is Al-Qaasim bin Umayyah Al-Hidhaa.
Ibn Hibbaan mentioned him in Al-Majrooheen (2/213) and said: “He was a shaikh who reported from Hafs bin Gayyaath many strange and weak narrations. It is not permissible to use him as a support when he is alone (in his narration).” Then he reported this hadeeth from him and commented upon it, saying:
“There is no source for this found in the sayings of the Messenger of Allaah صلى الله عليه وسلم.” I say: This hadeeth has also been reported by At-Tabaraanee in Al-Kabeer (22/53), Musnad Ash-Shaamiyeen (384), AlQadaa’ee in Musnad Ash-Shihaab (917-918) and Abu Nu’aim in Al-Hilyah (5/186). And it is also succeeded by ‘Umar bin Isma’eel bin Mujaalid found in At-Tirmidhee, Abu ash-Shaikh in Al-Amthaal (202) and Al-Khateeb in At-Taareekh (9/95-96). However, there is no point in that, since ‘Umar is matrook (rejected).
 The discussion of this has been stated previously in detail.
 Reported by Abu Nu’aim in Akhbaar Asbahaan (1/161) Al-Khateeb in his Taareekh (13/279) and Ibn Al-Jawzee mentioned it in Al-Mawdoo’aat (2/83). Al-‘Ajaloonee in Kashf-ul-Khufaa (2/343) added to that by attributing it to Ad-Daylamee. The hadeeth is reported through other paths from ‘Alee and Hudaifah, however they have severe weaknesses in them. See Al-Laalee Al-Masnoo’ah (2/293-295) of As-Suyootee and Mukhtasar Maqaasid-ul-Hasanah (pg. 83) of Az-Zurqaanee and Ad-Durr–ulMultaqitt (pg. 22) of As-Saghaanee.
Source: From the al-ibaanah eBook :
The Difference between Advising and Condemning – Imaam Ibn Rajab