What the Bible says about Bears Long
(From Forerunner Commentary)
Scholars seem to have a hard time with the clause "though He bears long with them." What it probably means is, "And shall God not avenge His own elect who cry out day and night to Him, though He delays His response to them?" He restrains His response; He holds it back from them for a little while.
Richard T. Ritenbaugh
Forbearance