It is a bit difficult to understand, however, why the Torah inserted the tochacha between the sections that deal with yovel. Abarbanel addresses this point, but I like the idea suggested by the Ishbitza. The theme of the parsha of archin is pidyon – redemption of pledges. The Ishbitza suggests that the idea of redemption should be understood more generally. Faced with a disheartening list of punishments, the Torah ends the parsha by telling us that all is lost; there is always an opportunity to redeem onself. Excluding the first pasuk of "Vayidaber Hashem el Moshe…" and the last pasuk which closes the parsha, there is an exact pasuk by pasuk match between the thirty-three pesukim of parshas archin and the thirty-three pesukim of tochacha. Every punishment has an escape clause should a person sincerely return to Hashem.
My wife thought of a slightly different formulation along these same lines. By connecting archin to tochacha perhaps the Torah is teaching that punishment itself is a means of redemption. G-d does not punish merely to cause pain; he punishes for the sake of kaparah and to teach us to change our ways.