Omprakash Ji
YAMA, the first step of Ashtanga Yoga is described in 30th Sutra of Patanjali Yoga as under:
AHINSASATYASATE BRAHAMCHARAYA PRIGRAHA YAMA (YOG 2/30)
  1. Ahinsa (Non-Violence)
  2. Satya (Truth)
  3. Asateya (Non-stealing)
  4. Brahamcharaya (Celibacy)
  5. Aprigraha (renunciation)
  1. Ahinsa:First Yama is : “Ahinsa”. “Ahinsa Parmo Dharmo” : Lord Mahavir also described as at the first place out of eighteen religious steps. Ahinsa is dealing with all beings with self-discipline. All human beings fear from sorrows. No one wants to die. Life and death are two sides of the same coin, and hence they should not be troubled, disturbed and distressed. A common man does violence under influence of sensuous feelings of Kama (sex), Karodha (Anger), lobh (Greed), Moh ( Attachment), Ahankaar (Ego) and Dar (Fear). Hence the follower of Yoga should step in for yoga only after leaving Ahinsa. After complete adoption of Ahinsa, the enmity towards others just vanishes. Even others coming in his contact leave enmity towards others.
  2. AHINSA PRATISHATHAYAM TATSANIDHO VAIRTAYAGO (Yog: 2/35)b) : Truth:The true knowledge of anything is Truth. To see, understand, describe anything in true form is Truth. To see reality in any other form, to alternate it, to describe differently is Untruthfulness. To speak fact is truth of voice, to put it in action is truth of the body and to adopt it in thought is truth of the mind. Ahinsa is the other name of Satya (Truthfulness). Ahinsa is said to be the other form of Satya. 
  3. SATYA PRATISHATHAYAM KRIYAFALAM SHRAPTAM (Yog: 2/36) : Always after being  egoless, disciplined, leaving untruthfulness, one should speak truth in the interest of all. Nowadays, in our routine, there is no place for truthfulness. Every moment, untruthfulness prevails. If everyone speaks truth, the standards of morality in society will improve. Once truth penetrates in mind, body and action, whatever the person says, truly happens. The truth gives respect in the society and motivated mind towards yoga. Asteya (not to steal/ burglar): To take away others money, wealth & rights is Stealing. To snatch others social, religious or personal rights, to give or take bribery, to measure less, to take higher prices, to adulterate,  to misuse others goodwill is stealing. When follower leaves stealing in mind, speech  and action, he becomes confidential to all. All good things automatically come to him. So, the person after leaving sense of stealing, gets motivated towards Yoga.
    ASTEYA PRATISHTHAYAM SARVORATNOPASTHANAM (Yog 2/37)
    d).
  4. Brahamcharya (Celibacy): Brahamcharya ( Celibacy) to get victory on senses by not losing semen by masturbation or any method. Only that can follow celibacy fully , who does not consume eatables destroying celibacy, not to see such scenes or hear such talks creating excitement. Vices such as wine, smoking etc wipe out celibacy. The other meaning is to adopt conduct of Bramaha. To follow celibacy is very difficult and only saints & seers can follow it completely. By following celibacy with mind, speech and actions, one gets power, vigour and strength.
    BRAHAMCHARYA PRATISHATAM VIRYALABHA   (Yog 2/38)
    e)
  5. Aprigrah:(renunciation) Parigrah means to accumulate more money, wealth, possessions than one’s needs. The accumulation of more wealth than required results in ego & enmity.  There is imbalance in nature. Hence follower of yoga should use the minimum things.In the universe, whatever is seen is created by God. Hence, while consuming anything, do it with feeling of surrender treat it ,it belongs to God. Never get engrossed in this. Because, the whole wealth belongs to whom ? Nobody. It is owned by God only. The follower of Aprigrah, gets good thoughts in mind and gets carried away in prayers of God after keeping  himself aloof from the worldly possessions.The relationship with Yama is social. Hence, the one who conducts against Yama does not deserve Yoga. The person not following Yama indulges in immoral influences. Hence to revert such person to society, the negative impulses has to convert towards positive thoughts. 
    APRIGARAHASATHEARYA  JANAMKATHANTA SAMBODHA (Yoga 2/39)