Was; rather, is. As a bear...as a lion. The comparison of the enemy to a lion is not uncommon; see e.g. Jeremiah 4:7; Jeremiah 5:6 (see note); Jeremiah 49:19; Jeremiah 1:1-19 :44; Psalms 10:9; Psalms 17:12; Job 10:16.
The bear is only once mentioned in such a context (Hosea 13:8). The two latter passages may possibly have been in the mind of the writer, as Jehovah is in both the subject of the comparison.