Jami` at-Tirmidhi Book 27, Hadith 12
the Messenger of Allah said: "A son could not do enough for his father, unless he found him as a slave and purchased him to set him free."
"Three supplications are accepted , there is no doubt in them (about them being accepted): The supplication of the oppressed, the supplication of the traveler, and the supplication of his father against his son."
" Abu Al-Laithi complained(of an illness). So 'Abdur-Rahman bin 'Awf visited him. He said: 'The best of you, and the most apt to maintain good relations, as far as I know, is Abu Muhammad('Abdur-Rahman bin 'Awf). So 'Abdur-Rahman bin 'Awf' said: 'I heard the Messenger of Allah saying : "Allah, Most Blessed and Most High, said: 'I am Allah, and I am Ar-Rahman. I created the Rahim(womb), and named it after My Name. So whoever keeps good relations with it, I keep good relation with him, and whoever severs it, I am finished with him.'"