Don't use the gift of speech to go against Hashem and His people. We take our speaking abilities for granted until one day we have laryngitis and then we can't say a word. A few months ago, when I was unable to speak or sing, I looked at others who could speak, with longing and yearning, hoping to be able to be like them. Let us not wait for when we don't have the gift of words to appreciate what we have. Let us think about speech as a great gift from G-d to be used to bring happiness and blessing to others, and to pray to Hashem with.
Commentators note that the snakes bit the people and the image of the snake was the cure.
Rabbi Chaim Shmuelevitz explained that when a person hits someone, it comes from anger and hatred, but when he helps another person, it comes from compassion and love. With Hashem, however, even when He causes a person to suffer, it comes from His compassion and love. In the overall scheme of things a person gains from that suffering. It is either atonement, it serves a lesson to teach a person to improve, or it elevates a person. Therefore, the smiting and the cure can be from the same thing because both come from the attribute of love.