Is there a Hadeeth in which a man came to the Prophet, sallallaahu ‘alayhi wa sallam, and told him that he loves Allaah, so the Prophet, sallallaahu ‘alayhi wa sallam, told him that he would afflicted as a result. Then the man told the Prophet, sallallaahu ‘alayhi wa sallam, that he loves him, so the Prophet, sallallaahu ‘alayhi wa sallam, told him that he would suffer from poverty?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

After investigation, we have not come across a Hadeeth with this meaning. However, the meaning of the last part of this Hadeeth is mentioned in the Hadeeth narrated by ‘Abdullaah ibn Mughaffal . In this Hadeeth a man told the Prophet, sallallaahu ‘alayhi wa sallam, that he loves him, then the Prophet, sallallaahu ‘alayhi wa sallam, told him that he would soon be afflicted with poverty. At-Tirmithi narrated this Hadeeth and graded it as Saheeh. However, Al-Albaani graded this Hadeeth as very Dha‘eef. Shaykh Muhammad ibn Saalih ibn Al-‘Uthaymeen said that this Hadeeth is not Saheeh, and that there is no relationship between richness and the Prophet's love: some rich people love the Prophet, sallallaahu ‘alayhi wa sallam, and some poor people hate him, sallallaahu ‘alayhi wa sallam.

We have not come across the first part of the Hadeeth you mentioned. However, it is well-known that one is afflicted if he loves Allaah as this reflects strong faith. The toughness of affliction is proportional to one's strength of faith. The Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said that the toughness of the affliction of a person increases in proportion to the strength of his faith: (i.e. the stronger the faith, the tougher the affliction) and that affliction removes all sins and renders the Muslim sin-free. [Ahmad]

Allaah Knows best.