It is the grace which pervades the whole nature, mellowing all which would have been harsh and austere. The word is descriptive of one's disposition and does not necessarily entail acts of goodness as does the word agathosune , active benignity. Chrestotes has the harmlessness of the dove but not the wisdom of the serpent which agathosune shows in sharpness and rebuke. It's interesting that this is the same word translated useful. This suggests that without gentleness we are useless.
Gentleness is a disposition.
It is an attitude that is concerned with the welfare of others. We need an attitude of gentleness to drive us to acts of goodness. I know a man who prays every morning for God to give him some revelation of the Word that he can carry in his heart for that day. Then he asks God to bring someone to him that he can share it with who needs to hear it. This is a devotion to other peoples good.