From en and ischuo; to invigorate (transitively or reflexively) -- strengthen.
see GREEK en
see GREEK ischuo
1. intransitive, to grow strong, to receive strength: Acts 9:19 (here WH Tr marginal reading ἐνισχυθη); (Aristotle, Theophrastus, Diodorus, the Sept.).
2. transitive, to make strong, to strengthen (2 Samuel 22:40; Sir. 50:4; Hippocrates leg., p. 2, 26 ὁ χρόνος ταῦτα πάντα ἐνισχυει); to strengthen one in soul, to inspirit: Luke 22:43 (L brackets WH reject the passage).