'Threshold' in the Bible

In those days, when Mordecai is sitting in the gate of the king, hath Bigthan been wroth, and Teresh, (two of the eunuchs of the king, the keepers of the threshold,) and they seek to put forth a hand on king Ahasuerus,

and it is found written that Mordecai had declared concerning Bigthana and Teresh, two of the eunuchs of the king, of the keepers of the threshold, who sought to put forth a hand on king Ahasuerus.