Why must Guan Eng and Betty Chew be spared?

Lim Kit Siang wants Prime Minister Muhyiddin Yassin to abuse his power and interfere in the process of the law and instruct the Attorney-General to drop the case against Lim Guan Eng’s wife, Betty Chew. But when Najib Tun Razak and Rosmah Mansor are arrested and charged they say Malaysia’s legal system is good, just and fair. Why must Guan Eng and Betty Chew be spared punishment and be given immunity from the law?