What commandment sums up all the other commandments like not bearing false witness and not coveting?
The commandment that comprehends the others is "Thou shalt love thy neighbor as thyself." When love is operating, it works no ill to a neighbor, so love is the fulfilling of the Law, including prohibitions against false witness and coveting.
Les explains that the commandments—not committing adultery, not killing, not bearing false witness, not coveting, and any other commandment—are briefly comprehended in the saying, "Thou shalt love thy neighbor as thyself." He points out that love worketh no ill to his neighbor, so love is the fulfilling of the Law. If Christian love is operating, a believer will not commit adultery, kill, bear false witness, or covet; love is the key and is simple and practical.
For this, Thou shalt not commit adultery, Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false witness, Thou shalt not covet; and if there be any other commandment, it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself.