I saw a picture of a spanner. It can usefully loosen or tighten a nut or a bolt. We can liken this to words that encourage when needed as well as positively help in discouraging a wrong course of action. Both directions can be useful . However, we also have an English expression of "a spanner in the works" which indicates a person or thing which prevents the successful implementation of a plan. Let's ask Jesus (God's Word) and the power of His Holy Spirit to enable us to choose our words carefully.