The example first praises courage, then yields the further suggestion that the person's continuing life is a benefit to the world. The second commendation is deliberately derived rather than merely appended as an independent compliment.
«لو حويته» supplies the hypothetical condition; the possibility of prolonged life follows, and «لهنت الدنيا» turns that outcome into another praise.
Istitbāʿ therefore requires a meaningful, intended dependence between the two commendations.