The claim "it's always God's will to heal sickness" is arbitrary — the apostles themselves suffered illness (Timothy's stomach issues, Trophimus left sick, Epaphroditus nearly died) while doing miracles.

Word of Faith teachers arbitrarily draw a line at sickness — you can suffer persecution according to God's will (1 Peter 4:19 explicitly teaches this), but not illness. Apostolic counterexamples: Paul had the thorn in his flesh (a physical ailment God declined to remove); Timothy had regular stomach issues and Paul prescribed wine rather than prayer (1 Tim 5:23); Trophimus was left sick at Miletus (2 Tim 4:20); Epaphroditus nearly died from a prolonged illness while doing missionary work with Paul (Phil 2:25-27). Paul healed crowds but left these companions sick. The distinction is arbitrary: "You can't get a cold according to God's will, but a mob can beat you, stab you, and cut off limbs and that's okay?"