All human beings seek tranquility and peace of mind, searching for ways and means for attaining real mental satisfaction. But the question is how is it obtained really?
The Quran has associated tranquility and peace of mind with the fulfillment of physical needs. One cannot have mental satisfaction unless one’s basic physical needs are fully met. Allah sets forth, in the Quran, the example of a city which enjoyed perfect peace and tranquility and means of sustenance were coming to it in abundance from every quarter. Here, Allah has mentioned tranquility and peace along with ‘means of sustenance’ and has contrasted tranquility with ‘hunger’ or ‘emptiness of the belly’. In Sura Ar-Rad verse 28, Allah says that being mindful of His Laws & Commands ensures the tranquility of the hearts. “Whoever turns away from His Laws & Commands, his means of subsistence will be restricted”. Here again, there is a connection between means of subsistence and the tranquility of the hearts.
Although fulfillment of one’s basic physical needs is important for having a real peaceful and tranquil mind, Allah has warned in the Quran that those who content themselves only with the petty delights of the worldly life and do not look beyond it, and neglect Allah’s Messages, their abode will be the Fire. Allah says, “Woe unto him whose efforts revolve around gathering (merely) material possessions and counting them; thinking as if his wealth will help him live forever! Nay, he will be flung intoalhutamati; that is the fire ignited by Allah, the flames of which engulf the hearts. ” Besides, Allah says, “The mutual rivalry for accumulating (more and more wealth and other worldly gains) diverts you (from the real purpose of your life), till such time that you reach your graves. So there has to be a balance between meeting one’s basic physical needs and indulging in the race of accumulating wealth and worldly possessions for their own sake.
The Quran not only mentions the tranquility or peace of mind related just to the fulfilment of physical or material needs but it also alludes to the mental satisfaction that comes after intellectual contentment and removal of psychological perplexities – after getting answer to the “how?” question and not just staying content with the answers to the “what?” and “who?” questions. It reminds of Abraham who said to his Lord, “My Sustainer, show me how You revive the dead.” Allah said, “Do you not believe?” Abraham said, “Yes I do, but I wish to reassure my heart. ” So in order to have a reassured heart devoid of any doubt or perplexity, it is important to have the “how?” questions satisfactorily answered. That is, it is not only important to know what are Allah’s Laws but it is also necessary to know how these Laws work. This is the way of Abraham, the way wherein, Allah says, is an excellent example for us to follow.
In summary, it can be said that the tranquility and peace of mind comes through being mindful of Allah’s Laws and Commands (which is not just knowing what His Laws are but also understanding how His Laws work) and then living by His Laws and Commands. By doing so, not only our physicals and material needs shall be met but we shall also achieve psychological and intellectual contentment. However, Allah tells those who have attained tranquility and peace of mind by following His Laws, that they cannot enter the blissful society of Jannah individually but through collective living by joining the group of people who are obedient to Allah.
 Al-Quran, Sura Al-Maeda (5) verses 112-113: When the disciples said, “O Jesus, son of Mary! Could thy Sustainer send down unto us a repast from heaven?” [Jesus] answered: “Guard yourself [against the inevitable consequences of violating the laws and command] of Allah [by careful observance], if you are [truly] believers!” Said they: “We desire to partake thereof, so that our hearts might be set fully at rest, and that we might know that thou hast spoken the truth to us, and that we might be of those who bear witness thereto!”
 Al-Quran, Sura An-Nahal (16): verse 112
 Al-Quran, Sura An-Nahal (16): verse 112 (compare the words aljooAAi and mutma-innatan in the verse)
 Al-Quran, Sura Ta-Ha (20) : verse 124
 Al-Quran, Sura Yunus (10): verses 7-8.
 Al-Quran, Sura Al-Humaza (104): verses 1-7
 Al-Quran, Sura At-Takathur (102): verses 1-2
 Al-Quran, Sura Al-Baqara (2): verse 260
 Al-Quran, Sura Al-Mumtahina (60) : verse 4
 A-Quran, Sura Al-Fajr (89): verse 27-30