'Added' in the Bible

while God added his testimony through signs, wonders, various miracles, and gifts of the Holy Spirit distributed according to his will.

He added an oath, in order that, through two unchangeable things, in which it is impossible for Him to prove false, we may possess mighty encouragement--we who, for safety, have hastened to lay hold of the hope set before us.

and a sound of a trumpet, and a voice of sayings, which those having heard did entreat that a word might not be added to them,