According to Islamic resources, people will experience enormous blessings in the reappearance era. These blessings can be divided into two main groups, namely "Material blessings" and "Spiritual blessings". Some of them are mentioned briefly in below:
Establishment of justice
He is the just person for whom all are waiting. At the appearance era, justice will be done to everybody as sun rays penetrate through their houses. Justice will be inclusive in the sense that it will cover everyone no matter if he is beneficent or not. Also, he will offer the previous prophets' books without any deviation; he will judge among the Jews by Torah, among Christians by Gospel and among Muslims by the Holy Quran. At that time, everyone will take back his/her rights.
Establishment of security
During his governorship, security will be provided in the entire world; oppressors will be perished; plunderous and seditious people will be removed; and all the routes will become safe.
People's relish for religion
Due to his appropriate method for inviting people, they will have relish for religion and worship; those expelled from religion will return to Islam hopefully; alterations (in religion), disbelieving, and oppressions will be eradicated in his era.
Improvement of moral sense and logical powers
Improvement of science and knowledge
Besides the two portions of science which are brought by previous prophets (PBUT), the remaining twenty five portions will be revealed by Imam Mahdi (PBUH) in the reappearance era. He will fill the earth with science and knowledge just as he filled it with justice. With his favor, the hearts of faithful people will get filled with science.
Nature assisting faithful people
Since faithful people support Mahdi (PBUH), the earth and the sky will flow their blessings towards them, and their life will be full of blessings. There will be rain; trees will become fruitful; and plants will grow out of ground.
Economic ease for all people
At that time, people will have a merciful governor. He will grant all people in such a way that no one has done before (generously and equally). Because of this economic safety, there will be no need to amass wealth or to accumulate properties.
Social convenience
Continuation of the pious' governorship on earth till the resurrection day
The governorship of Imam Mahdi (PBUH) is the beginning of the governorship of Prophet Muhammad's(PBUH) household on earth; that is actually the government of the pious which was promised by the Holy Quran, the Torah, the Psalms, and other scriptures. There is no definite period of time specified for this government, and it will continue until the resurrection day.
Final victory
Imam Mahdi (PBUH) is destined to gain nothing but the final and permanent victory; hence, he will be among people just like his fathers.
source : roshd