God does not allow an unclean person to touch the tithe he is giving to God. The full meaning of this statement can be made explicit. Alternate translation: "when I was unclean according to the Law" or "when the law says I cannot touch it" (See: [[rc://en/ta/man/jit/figs-explicit]])
Here "voice of Yahweh" is a metonym for what Yahweh says. Both statements share similar meanings. They emphasize that the person has obeyed all of God's commands. (See: [[rc://en/ta/man/jit/figs-metonymy]] and [[rc://en/ta/man/jit/figs-parallelism]])