Covenants

From the 100-Minute Bible (5 The giving of the Law):

God made a covenant with the people of Israel; he would care for them, and they would obey his commandments.

I suspect that, for many of us, subconsciously perhaps, this is still our agreement with God. We shall do our best, to keep his laws, to help other people, and in return, we expect him to look out for us. If something bad happens to us (or someone we know, or know of), our first question is 'why?' And, for myself, I wonder if God is punishing me for some wrongdoing. And when we hear of natural disasters, we comment on the injustice - why were these people singled out?

Of course, I'm touching on a huge, and difficult topic. I just want to consider one tiny aspect of the question. Do we (believers, Christians) live under the old covenant (we do our part, God does his), or have we grasped the new covenant? Or do elements of the old covenant still apply under the new? Does God punish wrongdoing? Do we experience what some people call chastisement? Does God deal with us as a parent deals with a child? And if God is prepared to deal severely with us, to purge us of wrongdoing, should parents have freedom (and backing) on occasion to deal severely with their children?