The prophet said: Verily Allah said to the world, Tire and wear out the one who serves you, and serve the one who rejects you. (Amali al saduq, page 230 #9)

What does this hadith mean? Is it saying that we shouldn't strive for anything in this life. If so then why is it that great things are achieved when someone works really hard. For example RasulAllah worked hard and achieved the highest of rewards

What is meant by this hadith is to pursue a materialistic life. The Prophet (a) is teaching us to serve God, live a decent life, not to be extravagant, fulfill family obligations, have a good job and prepare for the Hereafter. And we should avoid trying to just amass wealth, become famous and pursuing power. Some people work so hard just to make more and more money. They’re never satisfied. Some people pursue haram endeavors, such as haram singing/music. Such people are not at peace. Studies show that over 70% of musicians and singers (despite being famous and having millions of dollars) suffer from depression, and suicide rates are the highest among them. They don’t have quality of life. The Prophet (s) is teaching us: work for God, your family, for humanity, fulfill your religious obligations, and God will give you a quality life. But if you are obsessed with money, fame and power, your heart and soul will never be at peace. You just want more and more without ever getting satisfied.