Shias, Sunnis and non-Muslims admit incapability in grasping Imam Ali’s spiritual status
One chapter is the spiritual positions of the Commander of the Faithful including his monotheistic understanding, his act of worship, his closeness to God and his purity. These are things whose depth and truth are really beyond our reach. All outstanding ulama - including Shia and Sunni ulama and even non-Muslim scholars - have said that they are not able to understand this part of the Commander of the Faithful's (a.s.) personality. This part of his life catches everyone's eyes with its loftiness and enlightenment. They cannot understand the different dimensions of his life. This is one part of his life.
When Ibn Abi al-Hadid, a Sunni and Mu'tazili scholar, narrates one of the sermons of the Commander of the Faithful (a.s.) - which is about monotheism - in his commentary on Nahjul Balaghah, he says, "Ibrahim al-Khalil al-Rahman should be proud of having such a son". Many prophets emerged from Ibrahim's descendants. However, he says this only about the Commander of the Faithful (a.s.). He says, "Ibrahim al-Khalil al-Rahman should say to this son of his, ‘You made certain statements in your monotheism sermon about the Arabs' follies. I could not make such statements about Nabts' [a Bani Israel tribe] follies and I could not illustrate the same truths as you did'". Notice that the narrator is a Sunni and Mu'tazili scholar. This is one part and one chapter of the Commander of the Faithful's (a.s.) life and it has many unknown dimensions. This part of his life is really a deep ocean.