In this Quran verse, Allah tells the believers to have complete “tawakkul” and trust on Him and not to call upon others for help.
And verily, if you ask them: “Who created the heavens and the earth?” Surely they will say: “Allah (has created them).” Say: “Tell me then, the things that you invoke besides Allah – if Allah intended some harm for me, could they remove His harm? Or if He (Allah) intended some mercy for me, could they withhold His Mercy?” Say: “Sufficient for me is Allah; in Him those who trust (i.e. believers) must put their trust. “
Quran (Surah Az-Zumr, Verse 38)