'Once' in the Bible

Now therefore forgive, I pray thee, my sin only this once, and entreat Jehovah your God, that he may take away from me this death only.

And Aaron shall make atonement upon the horns of it once in the year; with the blood of the sin-offering of atonement once in the year shall he make atonement for it throughout your generations: it is most holy unto Jehovah.