A story about income and charity:[1]
The 1st Chabad Rebbe, Rabbi Shneur Zalman of Liadi, had a student by the name of Reb Tzadok. This Tzadok was a peddler of housewares to the various inns in his vicinity. Throughout the week he would sell his merchandise and he would return home for Shabbos.
This chossid was accustomed to say that when he made more than he usually did he was sure that when he arrived home there would be a messenger from the Rebbe or a letter that requested a sum of money to support a worthwhile cause.
He was always exceedingly happy that the almighty gave him the opportunity to support a cause of the Rebbe.
When G-d grants us more money than we were expecting to make, it is not to splurge on some physical pleasure, but to support a charitable cause.
[1] Sefer HaSichot, Summer 5700, Pg. 136
