It’s not entirely clear where this idiom originated, though some it started in Irish pubs where gambling was common.  A person might boast that they could do something and another person would challenge them to bet on it.  The theory being that if they were unwilling to gamble money on what they were talking about, they were just talk and basically full of it.

Today, it basically means that you need to back up what you’re saying with your actions.  So, what might that look like?  For example, you could say something along the lines of “Have you noticed the trash that seems to collect on that corner? I think someone should do something about it.”  The person you’re telling it to suggest that YOU could go out and pick it up, or organize your neighborhood to have a clean up day in order to ‘put you money where your mouth is’.

One definition I found was

to support something that you believe in, especially by giving money If people are really interested in helping the homeless they should put their money where their mouth is.

We also use the expression “Talk is cheap.”  The other day I saw a bumper sticker that read “Tithe if you love Jesus, anyone can honk.”  Meaning it’s very easy to complain about the state of things, and a lot harder or more expensive to actually do anything to change the situation.  It’s easy to say we want to support the advancement of God’s kingdom on the earth, but another to write the check or go online and give.

So, let’s evaluate our lives, and decide if we’re a honker or a tither, a mouther or a mover, a complainer or a changer.