Difference between Performing hajj on behalf of Others Voluntarily or for Payment

Q: Does performing hajj on others’ behalf for payment have the same rules as doing so voluntarily on behalf of another person or one of the Imams (a.)?

What are the differences?

A: Ruling of niyabi hajj (hajj performed on others’ behalf) apply to both, voluntarily and for payment. Of course, there are two types of hajj on others' behalf, obligatory and mustahabb. However, in hajj on others’ behalf done for payment, the items stipulated within the hiring contract in addition to those commonly observed — whether mustahabb practices, those done for caution or some etiquettes — should be observed while observing the same in voluntary hajj is not a must.