Yama and Niyama 

The following is extracted from Oki-sensi's book 'Meditation Yoga'. (http://okidoyoga.org.uk/books.html)

Yama and Niyama are an autonomous morality which is self-imposed, not laid down by an imperative authority, 
and a natural morality which prohibit only those actions and behavior that are opposed to the development 
of mind-heart, body and lifestyle. 

Yama are the basic daily moral codes which protect the mind-heart against disturnbances. 
The five aspects presented in Patanjali's Yoga-Sutra are:
 
1. No killing
2. No falseness
3. No stealing
4. Chastity
5. no coveting

Niyama are recommendations for a harmonious human life rather than moral codes. 
These five aspects are:

1. Cleaniness - in the meaning of 'to keep the mind-heart undisturbed by immoderate desires, thoughts and emotions'.
2. Satisfaction - in the meaning of 'to experience content mind-heart, whether or not your desires are fullfilled'. 
3. Order - in the meaning of 'a state in which everything is according to the law of nature'.
4. Study and Research - in the meaning of 'to make a sincere effort to comprehend the truth and to see everything in its reality'.
5. Concentration on God - in the meaning of 'to deepen our toughts about life and to maintain the purity of mind-heart'. 

Oki-sensei views 'God' as 'the fuctioning of the Lifeforce itself'.