That is, if we do not sow the seeds of righteous deeds in the few days of our life here, the opportunity will be lost for ever. When we reach the threshold of the other world and death seizes us, deeds come to an end., hopes are extinguished. If, God forbid, we continue to remain in the slavery of lusts and the captivity( of various carnal desires until the Angel of Death arrives, it is possible that Satan may achieve his ultimate objective of wresting away our faith. He may treat us in such a fashion and metamorphose our hearts to such an extent that we may depart from the world as enemies of God and His prophets and awliya'. If that happens, God knows what calamities, what darkness and what terrors await us.
So, O base self! O negligent heart! Awake from thy sleep and arise to confront this enemy who for years has subdued you and made a captive of you, who drags you whenever he wants and commands you to perform every ugly and destructive deed! Arise and bust these bonds! Sever these chains! Seek thy freedom and throw away(get rid off) this disgrace and indignity. Wear the girdle of servitude to God, the Almighty and the Glorious, that you may be free from every kind of servitude and slavery, that you may attain to the absolute kingdom of God in both the worlds.
My dear, although this world - being the believer's prison - is not the abode of Divine award and the place of the manifestation of God's kingdom, but should you come out(loom) from the captivity(detention) of the carnal self and submit to the servitude of God, make your heart a true monotheist and clear the dusts of plurality from the mirror of the spirit, and turn your heart's attention to the focal point of Absolute Perfection, you will witness its effects in this world itself and your heart will attain such an expanse that it will become the realm of the manifestation of God's total sovereignty, thus becoming greater than all the worlds. Hence He has said:
My earth and My heaven do not contain Me, but I am contained in the heart of my faithful slave. 
Such richness and contentment will then pervade your heart that all the outward and inward realms will become worthless in your eyes and your will, will become so mighty that it shall not attach itself to the corporeal and the celestial realms; rather it will not even consider them worthy of itself.
You have watched the bird's flight;
But should you remove the shackles of lust,
You will witness the flight of man.
source : Forty Hadith by Imam Ruhullah al-Musawi al-Khumayni