Imam Ali (PBUH) said: Surely, the completion of religion is due to the obtaining of knowledge and acting on it (accordingly), and beware that the obtaining of knowledge is more obligatory for you than earning wealth.

The mule has been deliberately bred by man since ancient times. The breeding of a jackass (male donkey) with a female horse (mare) is the most common and oldest known hybrid. A somewhat less common hybrid, the hinny, was also bred by crossing a female donkey with a male horse.

Imam al-Sadiq (PBUH) said: Safeguard your writings and books because soon the occasion will arise that you will be in need of them.

The exact origin of the mule may be somewhat difficult to determine, but its ancestry must begin with the origin of its parents - - the wild donkey and the horse. Mules, therefore, must have been bred in the wild in areas where both the wild donkey and horse occupied the same territory.

The name "liger", a portmanteau of lion and tiger, was coined by the 1930s. "Ligress" is used to refer to a female liger, on the model of "tigress".

In 1825, G. B. Whittaker made an engraving of liger cubs born in 1824. The parents and their three liger offspring are also depicted with their trainer in a 19th-century painting in the naïve style.

Imam Ali (PBUH) said: Acquiring knowledge is not possible while the body (person) is tranquil.

The liger enjoy swimming, which is a characteristic of tigers, and are very sociable like lions. Notably, ligers typically grow larger than either parent species, unlike tigons.

The history of lion–tiger hybrids dates to at least the early 19th century in India. In 1798, Étienne Geoffroy Saint-Hilaire (1772–1844) made a color plate of the offspring of a lion and a tiger.

Imam Zayn-ul-Abideen (PBUH) said: Were people aware of what lies in the obtainment of knowledge, they would pursue it even though they had to make voyages and endanger their lives to obtain it.

The Holy Prophet (S) said: He who searches for knowledge is similar to a person who fasts during the day and keeps vigil at night and is busy worshipping. If a person acquires a branch of knowledge, it is better for him than possessing as much gold as the height of Abu Qubais Mount which he would distribute in the way of Allah.