What is the ruling on seeking intercession through the status of a saint (wali), such as by saying: "O Lord, I ask You by the virtue of this saint, or by the blessing of this place"?

Intercession (Tawassul) is making something a means to achieve a desired purpose. It is of various types: permissible (mashru'), polytheistic (shirki), and that concerning which there is a difference of opinion. Polytheistic intercession is directing acts of worship to other than Allah, such as supplication (du'a) and sacrifice, believing that they will intercede on one's behalf. Allah the Almighty says: "We do not worship them except that they may bring us nearer to Allah in closeness." As for intercession concerning which there is a difference of opinion, it is seeking intercession through the persons of Prophets and righteous individuals and their status (jah). There are two opinions regarding this: The first is that it is an innovation (bid'ah) and a means to polytheism (shirk (definition)). They supported this by citing that 'Umar interceded through al-'Abbas after the death of the Prophet, peace and blessings of Allah be upon him. The second is that it is permissible. They supported this by citing the Hadith (definition) of the blind man. The preponderant opinion is the first one. It must be noted that if the person seeking intercession believes that Allah will not grant his need except through intercession by other than Him, then this is prohibited.