What is meant by Tawassul and Istighatha, and is it better to prohibit them as a preventative measure due to the disagreement regarding their ruling?

Seeking succor (Istighathah) is to ask for help when a hardship occurs. Seeking succor from a created being for something only Allah can provide is polytheism (shirk), because it is a form of supplication (du'a), and supplication is an act of worship that must be directed only to Allah Almighty.

There are different types of seeking nearness (Tawassul) to Allah Almighty. Tawassul through His names and attributes, and through one's own righteous deeds, is permissible and legislated by consensus. However, Tawassul through the status (jah) of the Prophet (peace be upon him) or others is a matter of scholarly disagreement. Among the forbidden beliefs is to think that Allah will not fulfill a need except by Tawassul through the status of a particular person. What Allah Almighty has legislated of the agreed-upon forms of Tawassul is sufficient.