The heart is devious above all else; it is perverse— who can understand it? I the Lord test the mind and search the heart, to give to all according to their ways, according to the fruit of their doings. Like the partridge hatching what it did not lay, so are all who amass wealth unjustly; in mid-life it will leave them, and at their end they will prove to be fools. (Jeremiah 17:9-11, NRSV
The Lord will search our minds and our hearts to give us what we deserve according to our ways, according to the fruit of our doing.
The Lord knows the reason we do the things we do. Is it out of the love that the Lord has poured into our hearts, or for our own gain?
The heart desires what it wants, but we must know if it is for the Lord or our own selfish gain. The Lord will always know.
Live for others, as the Lord lives for you!