The Holy Prophet (s) said “The worship of done by the one who earns his living on unlawful money is similar to a building constructed on sand.”[i]
[i] Bihar-ul-Anwar, vol. 84, p. 258
A short talk I did while in Karbala about the merits of visiting the shrine of Imam Hussain ع.
The Holy Prophet (s) said “Whoever desires to live my life and to die my death and dwell in the land of paradise, which my Lord has promised me, he should follow the guide of Ali ibn Abi Talib as he would neither take you out of guidance nor bring you into misguidance.” (Sunni source)[i]
[i] Mustadrak al-hakim vol 3 page 126