Rabbeinu Bechaye, in his introduction to פרשת כי תבוא, speaks about the importance of בטחון, faith. One’s בטחון should cause him to spread the wealth that Hashem gives him, to help the poor.
He should trust that Hashem will reward him for his בטחון. He should never think he will lose his wealth by giving charity. He should remember that צדקה תציל ממות, that charity saves one from death. We give in order that we will have. When one gives to the poor, it’s as if he returned that money to Hashem.
When it says that one must give of himself, he is also expected to use other gifts that Hashem gives him. For example, if one is blessed with a beautiful voice, he should use it to lead in prayer. If one is dexterous, he should become a מוהל. And if he is a good writer, he should use his talents, to write books for Hashem.
In short, we should have בטחון that if we use the gifts that Hashem gives us in the right way, we will be blessed.