How is Christ our Mediator?

Mala Chindongo explains in this video that Christ is our Mediator. There is only one between God and man. He stands in between God and us and makes peace for us. 

He does that by becoming a sacrifice. He laid down His life so that sinners might be saved. 

1 Timothy 5-7 (NKJV) - "For there is one God and one Mediator between God and men, the Man Christ Jesus, who gave Himself a ransom for all, to be testified in due time, for which I was appointed a preacher and an apostle—I am speaking the truth in Christ and not lying—a teacher of the Gentiles in faith and truth."