Hazrat Ali RA himself answers this question in Letter 31 as an advice to his sons: http://www.al-islam.org/nahjul/letters/letter31.htm#letter31
Do not seek help or protection from anybody but Allah. Reserve your prayers, your requests, your solicitations, your supplications, and your entreaties to Him and Him alone because to grant, to give, to confer and to bestow, as well as to withhold, to deprive, to refuse, and to debar, lies only in His Power. Ask as much of His Blessings and seek as much of His Guidance as you can.