Alma 42

The eternal nature and law of justice cannot be emphasized more as Alma testifies three times -

"Therefore, according to justice, the plan of redemption could not be brought about, only on conditions of repentance of men in this probationary state, yea, this preparatory state; for except it were for these conditions, mercy could not take effect except it should destroy the work of justice.  Now the work of justice could not be destroyed; if so, God would cease to be God."  (Book of Mormon | Alma 42:13)

"...if there was no law given, if men sinned what could justice do, or mercy either, for they would have no claim upon the creature?
22 But there is a law given, and a punishment affixed, and a repentance granted; which repentance, mercy claimeth; otherwise, justice claimeth the creature and executeth the law, and the law inflicteth the punishment; if not so, the works of justice would be destroyed, and God would cease to be God."  (Book of Mormon | Alma 42:21 - 22)

"For behold, justice exerciseth all his demands, and also mercy claimeth all which is her own; and thus, none but the truly penitent are saved.
25 What, do ye suppose that mercy can rob justice?  I say unto you, Nay; not one whit.  If so, God would cease to be God."  (Book of Mormon | Alma 42:24 - 25)

It is apparent then that a attribute of godliness is the law of justice.  God then cannot override His own laws because of love and kindness.