structural:scholar_edition, linguistic:paraphrasing, structural:expansion
Sufism

Some Sufi mystics advocate monism. One of the most notable being the 13th-century Persian poet Rumi (1207–1273) in his didactic poem Masnavi espoused monism. Rumi says in the Masnavi,

In the shop for Unity (wahdat); anything that you see there except the One is an idol.

Other Sufi mystics however, such as Ahmad Sirhindi, upheld dualistic Monotheism (the separation of God and the Universe).

The most influential of the Islamic monists was the Sufi philosopher Ibn Arabi (1165–1240). He developed the concept of 'unity of being' (Arabic: waḥdat al-wujūd), which some argue is a monistic philosophy. Born in al-Andalus, he made an enormous impact on the Muslim world, where he was crowned "the great Master". In the centuries following his death, his ideas became increasingly controversial. Ahmad Sirhindi criticised monistic understanding of 'unity of being', advocating the dualistic-compatible 'unity of witness' (Arabic: wahdat ash-shuhud), maintaining separation of creator and creation. Later, Shah Waliullah Dehlawi reconciled the two ideas maintaining that their differences are semantic differences, arguing that the universal existence (which is different in creation to creator) and the divine essence are different and that the universal existence emanates (in a non-platonic sense) from the divine essence and that the relationship between them is similar to the relationship between the number four and a number being even.