Helping Each Other In Holiness

Speaking of Matt 18:5-6 [“Whoever causes one of these little ones who believe in me to sin, it would be better for him to have a great millstone fastened around his neck and to be drowned”] R C Sproul gives the following food for thought:

"One commentator says that leading others into sin can be done in ways that do not involve false teaching. Failure to provide adequate pastoral care, for example, can make us unable to see trouble in the lives of others, leading us to overlook the need to rescue a sheep in danger of going astray."

Is it enough not to lead someone astray into sin, or should we be involved in preemptive strikes (so to speak) in helping and encouraging one another in holiness?