Ben kidnaps Jack specifically because he needs a spinal surgeon. Their dynamic is transactional from the start -- Ben offers information and freedom in exchange for surgery, and Jack turns the leverage back on him mid-operation. This sets the template for every interaction: Ben manipulates, Jack resists, and somehow they both end up doing what the other wanted. By Season 6, Ben is following Jack's lead genuinely for the first time. Their final dynamic -- Ben serving Hurley, who trusts Jack's judgment -- is the closest Ben gets to earning Jack's approval.

1. S2E15
   One of Them

   Ben (as Henry Gale) is captured. The mind games begin.

2. S3E6
   I Do

   Jack operates on Ben's spine and uses the leverage to demand Kate and Sawyer's release.

3. S4E14
   Dead Is Dead

   Ben is judged by the smoke monster. His power is broken.

Season 2: Ben manipulates everyone from a cell. Season 3: Ben holds Jack captive but needs him alive. Season 4: competing for control of events. Season 5: Ben tricks Jack into returning. Season 6: Ben finally stops playing games and joins the right side.