Vivekachudamani 27

ahankara adi dehantan bandhana jñanakalpitan | 
sva svarupa vabodhena moktumiccha mumuksuta || 
(Sankaracarya's Vivekachudamani 27) 

Mumuksutva is the burning desire to free oneself, by realizing one‘s true Self—from all bondage from that of egoism to that of identification with the body—which is bondage imagined due to ignorance. 

It has actually been seen that even after achieving so-called perfection, many karmīs, jñānīs, and yogīs become attached to material activities again. Many so-called svāmīs and yogīs give up material activities as false (jagan mithyā), but after some time they nevertheless resume material activities by opening hospitals and schools or performing other activities for the benefit of the public. Sometimes they participate in politics, although still falsely declaring themselves sannyāsīs, members of the renounced order. 

The perfect conclusion, however, is that if one actually desires to get out of the material world, he must take to devotional service, which begins with śravaṇaḿ kīrtanaḿ viṣṇoḥ: [SB 7.5.23] chanting and hearing the glories of the Lord. By doing devotional service one can be free from bondage. So to get this body means I have got material desires. This body. This is philosophy. Anyone who has got this material body, beginning from Brahma... He is considered the first creature within this universe, most intelligent, most learned, but still, because he has got this material body, he's not akama, without any material desires. He has got material desire. He wanted to become the supreme head of one universe. Just like we try to become supreme head of a family, then of a society, then of a nation, of a community. Then I desire to behead, also... Go on, go on, increasing. To lord it over. So, so long there will be a desire to lord it over, then we have to accept a body. It doesn't matter what kind of body. It may be Brahma's body, it may be the cat's body, it may be a man's body, it may be the bird's body, it may be a beast's body. That will depend on my desire. But if I have got any desire, material desire to fulfill, then I must be prepared to accept the next body, another. 

So if one wants to finish this business, accepting... And accepting a material body means to become subject to the laws of material nature. You get a material body, and if you want that "I shall not die," it is impossible. It is not good. Then you must die. Bhutva bhutva praliyate. You get a material body and again you give it up, and again you get it. This is going on. Therefore, Caitanya Mahaprabhu said, 
ei rupe brahmanda bhramite kona bhagyavan 
jiva guru-krsna-krpaya paya bhakti-lata-bija 
[Cc. Madhya 19.151] 

In this way, all the living entities, beginning from Brahma down to the microscopic germ, everyone is rotating in different species of life, in different planets, in different positions. Innumerable. As the living entities are innumerable, so varieties of bodies are also innumerable. Not innumerable, they are counted, 8,400,000 species of life. This is Vedic knowledge. Exactly giving the number. Exactly. 8,400,000. 

 Better to stop all those bondage and taking repetitive birth we should simply surrender ourselves to the Supreme Lord. There is no time for us to enjoy this material world. Enjoying means simply will create suffering.