Albert Barnes Commentary Luke 16:12

"And if ye have not been faithful in that which is another`s, who will give you that which is your own?" — Luke 16:12 (ASV)

Another man's. The word man's is not in the original. It is, If you have been unfaithful managers for another. It refers, undoubtedly, to God. The wealth of the world is his. It is committed to us as his stewards. It is uncertain and deceitful, and at any moment he can take it away from us. It is still his; and if, while entrusted with this, we are unfaithful, we cannot expect that he will grant us the rewards of heaven.

That which is your own. The riches of heaven, which, if once given to us, may be considered as ours—that is, it will be permanent and fixed, and will not be taken away as if at the pleasure of another. We may count on it, and look forward with the assurance that it will continue to be ours forever, and will not be taken away like the riches of this world, as if they were not ours.

The meaning of the whole parable is therefore expressed as follows: If we do not use the things of this world as we ought—with honesty, truth, wisdom, and integrity—we cannot have evidence of piety, and shall not be received into heaven. If we are true to that which is least, it is evidence that we are the children of God, and he will commit to our trust that which is of infinite importance, even the eternal riches and glory of heaven.