Is it necessary to rub thick hair vigorously during ghusl (ritual bath) after janabah (state of ritual impurity)?

In ghusl (ritual bath), water must be poured and made to reach all parts of the body, including the hair and its roots, ensuring the water reaches the scalp (the skin under the hair). Rubbing (dalk) is not obligatory unless the water's access to the skin depends on it. The jurists' opinions have converged on the obligation of water reaching all of the hair and skin, as the Messenger of Allah, peace and blessings be upon him, did.