From: Honen's Senchakushu. Pg 142
"... [It] is taught in the ... Amida sutra, if a man or woman single-mindedly and wholeheartedly thinks of A-mi-t'o Fo and desires birth [in the Pureland] for seven days and nights up to the whole of his or her life span, then all the buddhas of the six directions, as many as the sands of the Ganges, together will come and always protect him or her. This is why that sutra is known as the "sutra of protection." The "sutra of protection" means that [many buddhas] also prevent all devils and evil spirits from coming into contact with the practitioner; and also that they prevent sudden illness, sudden death, sudden and calamitous disasters for befalling him or her; and that they spontaneously eradicate all misfortunes and obstacles. Those whose practice is not wholehearted are excepted."
From: Honen's Senchakushu: passages on the selection of the Nembusu in the Original Vow. Translated and edited by Senchakushu English Translation Project.