According to Islam, the ultimate state of spiritual upliftment is referred to in the Quran as the 'soul at peace' in these words:

“[But to the righteous, God will say], ‘O soul at peace, return to your Lord, well-pleased, well-pleasing. Join My servants. Enter My Paradise.’” (89:27-30)

One who wants to be held deserving of Paradise in the Hereafter must prove that he is a complex-free soul (an-nafs-e-mutmainna). A complex-free soul is one who accepts the creation plan of God, who can give a positive response in any situation, good or bad, who develops no negative feelings in any adverse situation, and who never becomes proud or arrogant in a favourable situation. He is one who can face either situation with a balanced attitude. He is the one who stands up to the test by not allowing situations to negatively affect him but responds to them positively.

Our world is a world of differences, unwanted situations, and provocations, therefore, at all times we have to face predicaments that are not to our liking. This diversity of situations is a part of nature. Since no one can remedy this, one cannot have a world free of all these aspects. We have no option but to accept the world as it is. To pass the test of life, man is required to face all these odds with a tranquil mind. He is required to take them as a challenge and to do so in a positive way. Man is required to give a positive response even in negative situations. Those who prove themselves capable of doing this are complex-free souls. A complex-free soul does not mean a soul without complexes. A complex-free soul is one who is able to deal with all kinds of adversity. A complex-free soul exhibits the capacity to manage things rather than the capacity to eliminate them.

A complex-free soul is one who accepts God’s scheme: in return, God will accept him and reward him with eternal Paradise.

Source: Quranic Wisdom