Now understand it in the context of the mediation Paul commands in the preceding verses.
You can't, because it doesn't fit in your "me and Jesus, and I'm just an acquitted criminal, a 'snow-covered dungheap'" reformation theology.
Calm down, Campion. Just because RCC doctrine cannot be supported by Scripture you needn't lash out at me. Return to the Bible and learn the truth for yourself.
One God. One mediator. Saved by grace through faith in Jesus Christ.