We all make investments in the expectation that they would help us in the time of need. Investments can be classified based on when they start giving us returns, some of them might be short term(1-2 year), some medium(5-10 yrs) and some real long term(beyond 10 yrs ). Again, smart investors don't put all their money in one instrument, as they want to shield themselves from vagaries of the market and time. So they invest in gold, property, stocks and various other options. They keep getting rewarded from their investment and live a life of prosperity with all the comforts of this material world.
Now, drawing an analogy here, what should we do for attaining prosperity in the spiritual world. Charity is the investment which can help us grow in the spiritual work. There is a story in Mahabharatha of a Brahmana, who attained to the highest sate of SriVaikuntha, just by donating a handful of rice. Similar to material investment, we should do charity of different types. Some, which is very easy like feeding birds, animals or someone who is hungry or giving clothes to the needy. This is like short term investment. Some of the charity should be for causes like education, healthcare which helps the society in general and can be like medium term investment. Some of it should be set aside for religious & spiritual institutions which is like long term investment and would give results in this or next lives. Now, intelligent investors don't brag about their investments, similarly while doing charity the following line from Taittriya Upanishad should be remembered
shraddhayA deyam | Give with Faith,
ashraddhayA.adeyam | Give not without Faith;
shriyA deyam | Give in Plenty,
hriyA deyam | Give with Modesty,
bhiyA deyam | Give with Awe,
saMvidA deyam | Give with Sympathy.