Romans 10:31b

"... through the mercy shown you they also may obtain mercy."

Mercy is a repeal that's granted by someone in control, power or authority over another. One can ask, and even beg for mercy from another in such a position, and it may or may not be granted depending upon the grantor. Regardless, the decision is outside another's control, and this is why it's mercy.

Infinite amounts of mercy have been showered upon me and all who believe by faith in Jesus, more than I could undoubtedly ever know, me being finite of mind and breath. In fact, the writer of Lamentations says God renews His mercies everyday (cf. Lamentations 3:22, 23), and Paul goes on to state just a few sentences later in this chapter that God's depths are unsearchable and "His ways past finding out!" (cf. Romans 10:33)

Since it's indisputable that I've been the recipient of God's mercy, the question now becomes, "How do I respond?" Paul states that "through the mercy shown" me, others "may obtain mercy". I believe it's personal (note the pronoun), and not just between Jews and Gentiles (which is the context of this passage). I respond as follows: (i) In humility because I cannot boast that I had anything to do with the decision, (ii) in service because I'm eternally indebted to the Giver, and (iii) in worship because I am the subject of His Kingship. This response, if visible, may then cause others to know that forgiveness is available, mercy can be granted, and grace given if they too might humble themselves, acknowledge their lowly status, and ask for it. "...ask, and you will receive, that your joy may be made full." (John 16:24b)

What a remarkable place God has put me in today. May my knowledge of His mercy over me and my response to that mercy be the agent by which someone else might receive mercy.