There exists a belief which say in order for an exchange to be fair, there must be an even exchange of value between us.
This is true only in the context of you and I being separate.
The Truth is we are not separate; we are parts of the Whole that is the Universe, the Divine, God.
In that context, when you give to me and I receive, you are not lessened by your gift if I do not immediately respond in kind.
For a time I will be enriched to a greater extent than I was before, while by the act of unconditional giving you too become enriched.
Because we are each individual expressions of the Whole, the energy of giving continues its flow as I give to others as has been given to me.
And in so doing, the ever constant motion of the energy of God continues to weave its magic through all connected lives.