Tawassul and Wasilah

The four main schools of jurisprudence allow tawassul in all the 4 types.

1. By mentioning the beautiful names of Allah
2. One’s own good deeds
3. Through a pious living person
4. Deceased pious person

The first time tawassul through a deceased pious person (including Prophets and Messengers) was deemed impermissible was Imam ibn Taymiyya.