"Inward Parts"

Leviticus 1: 9 & 13

But the internal organs and the legs must first be washed with water.

This concerns the animal that is to be sacrificed and burned on the altar. It was to be cut up, butchered, into its parts. The internal organs were part of the burned part, as well as the legs, and were to be washed with water before being placed on the altar to be consumed by fire.

When Jesus washed His disciples' feet at the Last Supper, he told them that they wouldn't understand the full import of what He was doing until later. When Peter objected to having his feet washed, Jesus told him that they were already clean, but not every one (referring to Judas), only their feet needed the dust cleaned off. He meant that His coming Sacrifice would wash away the stain of sin from their "inward parts" and they would be completely clean in God's sight (see John 13:4-11).

O Lord, thank You for washing me, for washing my inner parts. Continue to wash my hands and feet daily as I walk in the dust of this World, so that I will be clean, whiter than snow, a vessel suitable for Your purposes. 

Even so, come, Lord Jesus!