Albert Barnes on Luke 16:11

Who will commit, &c. If you are not faithful in the small matters pertaining to this world, if you do not use aright your property and influence, you cannot expect that God will commit to you the true riches of his grace. Men who are dishonest and worldly, and who do not employ the deceitful mammon as they ought, cannot expect to grow in grace. God does not confer grace upon them, and their being unfaithful in earthly matters is evidence that they would be also in much greater affairs, and would likewise misimprove the true riches.

True riches. The graces of the gospel; the influences of the Spirit; eternal life, or religion. The riches of this world are false, deceitful, not to be trusted (Lk 16:9); the treasures of heaven are true, faithful, never-failing, Mt 6:19,20.

(4) "mammon" = "riches"