To know mercy one must know justice. One must also know his own debt to God. Get out the scale. Have you done anything to deserve the breath you receive, or the moisture you require, or the food you eat, or land to live on?
You say, "I work for a living. I buy all that I need." In principle, you buy only because someone has prepared for you what God has already given you freely. You buy, because you do not gather the resources yourself. You choose to enslave yourself to another for a wage in order to reap from them what you did not sow.
Some would say this is why we must all be agrarians. Some say this is the reason to empower government over all. I have learned that there is no way to repay God. Only obedience to Him justifies the blessings we receive, for in our weakness we cannot make, grow, produce, or even live without His help. He does not want us to enslave ourselves to any man or government for He is a jealous God. He is the one who has prepared all things for us.
The key to prosperity is obedience. Our obedience is the key to His mercy. In his mercy he does provide for all things for us. His commands are to love Him unconditionally and love others as we do ourselves. It is this love that leads us to serve others. As we can better provide a service we offer to others what they cannot for themselves. Thus learning charity, we accept the help others can provide better for us. This is called trade, though it is our God given tallents that make this possible. The more freely we trade we as a people prosper. All this prosperity comes from God and continues to be showered upon us until such time as we become complacent, proud, and forget our God. Let us not forget who is God and why we are industrious. Let us not withhold our abilities and means from our brothers. Let us show mercy as God has shown us.