Sima Guang, (1019 – 1086 AD), courtesy name Junshi, was an upright scholar, statesman, and poet during the Northern Song Dynasty (960 – 1127 AD). He compiled Zi Zhi Tong Jian, i.e., Comprehensive Mirror for Aid in Government, a general chronicle of Chinese history from 403 BC to 959 AD. It is the first comprehensive account of Chinese history and is considered one of the finest historical works. Sima Guang classified individuals into four groups based on their virtue and talents: the sagacious - those who have both virtues and talents; the foolish - those who have neither virtue nor talents; the noble - those who have virtue but no talents; and the sly - those who have talents but no virtues.
 
When it was time to appoint an official, the first choice would be a sagacious person, then a noble person. If neither a sagacious person nor a noble person could be found, it would be better to use a foolish person rather than a sly one. It was because individuals with talents but without virtue were most dangerous. They were worse than those who have neither talents nor virtue.
 
Sima Guang believed that a gentleman with talents could perform good deeds, whereas a sly person would use his talent to do evil things. As for the foolish, they do not have sufficient wisdom to perform evil deeds. Meanwhile, the sly  could easily demonstrate their treachery using their talents. If sufficient effort was put in, their work could result in much violence. It’s as if adding a pair of wings onto a tiger, and the damage done could be immeasurable.
 
Sima Guang further explained that a person with virtue was respected by others, and a person with talent was well-liked. However, a well-respected person could keep someone at a distance, but a well-liked person generally attracted people. Hence, as a scrutinizer, one may easily overlook the virtuous, but be overwhelmed by the talented. From history, almost all fatuous and self-indulgent emperors, treacherous officials, and prodigal sons were all talented people who lacked virtue. There have been too many examples of such people who caused the defeat of their countries or the loss of their homes. The infamous tyrannical emperors such as Yin Zhouwang (1105 – 1046 BC), Zhou Youwang (795 – 771 BC), Sui Yangdi (569 – 618 AD), etc. were all talented, but lacked virtue. They were all sly persons who brought calamity to their own countries.
 
Yin Zhouwang was especially intelligent and knowledgeable. He was very powerful physically and was capable of combating a wild beast bare-handed. However, he often covered up his mistakes, turned a deaf ear to advice, and showed disrespect to the Heavens. He was demonstrative and liked showing off his talent. He felt that the whole world was inferior to him, and he was cruel and brutal. He tortured loyal supporters with branding irons, cut open a woman's belly to examine the fetus, broke a person's bone to extract the marrow, and dissected his own uncle alive to get his heart. Finally, the feudal lords and his people turned against him. Yin Zhouwang was defeated by Zhou Wuwang (? - 1043 BC) and his kingdom was overthrown. He died in a self-immolating fire, and his name has ever since become a laughing stock in history.
 
Hence, Sima Guang reiterated that when selecting an emperor or appointing an official, virtue comes first.
 
Reference: Song History - Biography of Sima Guang
 

司马光的“德才观”
 
司马光（1019-1086），字君实，山西夏县人，北宋文学家、史学家，为官四朝，主持编纂了中国第一部通史《资治通鉴》，他是儒学教化的典范，历来受人景仰。
 
司马光看来，据人的才德情况，大概可划分为：才德兼备的叫做“圣人”，才德全无的叫做“愚人”，德行胜过才能的叫做“君子”，才能胜过德行的叫做“小人”。在选人用人时，司马光观点是必须重用圣人、君子，倘若无圣人、君子，宁可用“愚人”也不用“小人”。
 
究其原因，司马光认为，由于君子拥有才能可以行善，而小人拥有才能，会用以作恶。愚人想作恶，但由于才智不全不能得逞，而小人智谋足以实现他们的奸诈，勇力足以达成行暴，等于虎添双翼，它们危害之大无与伦比啊！
 
司马光进一步阐述道，有德行的人被人尊敬，有才能的人被众人喜爱。然而尊敬的容易疏远，而喜爱的却容易亲近。所以作为考察者，大多被人的才能所蒙蔽，而忽视了他们的德行。自古以来，国中的昏君、奸臣、家庭的败子，大多是才华有余而德行不足，以至于造成国破家亡的太多了。历史上臭名昭著的暴君殷纣王、周幽王、隋炀帝等都是有才无德、祸国殃民的小人。
 
特别是殷纣王，资质聪颖，见闻广博，勇力超常，能够空手与猛兽格斗，但是他却文过饰非，拒绝纳谏，怠慢天神。自我炫耀，认为整个天下所有人的本领都在自己之下。因此他残忍凶暴，炮烙忠良，剖腹验胎，敲骨检髓，活摘其叔心肝。结果四方诸侯和民众都背弃他了，终于被周武王伐灭，国亡身焚，为天下笑。
 
由此司马光一再重申，选君用臣，必须将德行置于首位。
 
据《宋史--司马光传》编译