Chandresh: Pranam to the soul and god inside you, one question is in my head, hart, soul and body everywhere right now. Why birth needed? If you say for purification of soul and to realization of the truth, How a soul became dirty or forgot the truth at the first place.
Swami Ram Swarup: My heartiest blessings to you for a long, happy life.

Purpose of soul acquiring body

Automatically srishti is created and automatically souls come in body of living beings according to good or bad deeds. Suppose, soul does not acquire body then it is a law that soul will remain in Sushupt avastha (like in coma). So what will be the use of man or woman who remains in coma for years together?

At the time of non-sexual creation, Vedas emanate direct from God and are originated in the heart of four Rishis. This all is for the benefit of human beings. So Vedas are also eternal as Vedas have not been written by anybody.

So wrong being in coma like stage is that soul will be considered lazy and will be of no use for himself and for others. People when see a person in coma, they feel sad and shower mercy for him. But I may tell here strictly that these lines are based on assumption only which is dangerous klesh as per Yog shastra Sutra 1/6 and 1/9 being Vikalp Vriti, I have explained this Vritti in comments (detailed description) of Yog shastra which may be read there. In short, Vikalp Vritti is that vritti in which one being a lazy person will be thinking and creating own stories, the fact of which is never seen on the earth. For example –Kapil Muni in his Sankhya Shastra sutra 5/52 states that such false knowledge is like a thought that man has horn on his head which is totally false. Secondly if someone says that the man is carrying bow made of horns of hare/rabbit. Whereas rabbit has no horns.

In Vedas God has advised only that if human being wants happiness and to be away from diseases, sorrows, tensions, problems, death etc, then he should follow the Vedas and must do worship of God, otherwise he may avoid Vedas and worship. So there is no compulsion in Vedas to worship God. On the contrary, it is mentioned “Swantrata hi karta” i.e., man or woman are free to follow or not to follow the Vedas but result will be awarded by God. So the knowledge of Vedas is given by the God for the benefit of human beings and not for the benefit of God. Secondly, We all use sun, moon, air, water, earth and every matter of the universe made by God for our benefit and the use thereof is already mentioned in Vedas. Then we become happy to utilize the same but still remain in diseases, problems, sorrows etc. Therefore if we obey spiritualism of the Vedas, we will really be happy. This is preached by God in Vedas. So it is upto the people. They may or may not follow the Vedas.

Yes, the God is not affected whether we praise Him or not but people are affected. Why? If we worship, we remain the happiest and if we do not worship we always remain in trouble, sorrows etc. God is our commander and even like our father. Father nurses and so does God while providing us with food etc. So there is only Almighty and omnipresent power in the shape of God who only selflessly nurses us and makes all materials available to us for our benefit. So if in return we do not thank Him then we are indulged in thanklessness which is further a great sin. A gentleman always try to thank the others for the deeds which have been done for him for his benefit. But if we do not remember God who is really more than an ocean/source of all benefits to us then what why will we not be called the most thankless.
Souls are uncountable but God is one who is omnipresent. The soul who has got moksha will remain liberated in the next creation also and he even experiences the time of final destruction and the time of next creation

However, soul gets moksha and not body. A yogi who has got moksha touches electric wire knowingly or unknowingly he will die. But soul residing within his body will not be affected. Or somebody gives poison to a liberated person, the effect of poison will be in his body and he will die, then too soul always remains unaffected. Question of not following the Vedic path after moksha never arises.

Naturally soul is not dirty and therefore, soul never becomes dirty. However, soul gets attracted towards the prakriti made worldly, materialistic articles and therefore, soul forgets his real, eternal and pure shape. The soul realizes himself i.e., realizes his original, true and pure shape by following vedic path i.e., after studying Vedas to follow it, doing daily agnihotra from ved mantras, daily name jaap of God-Om and after doing hard practice of Ashtang Yog philosophy and attaining Samadhi.(Yajurved mantra 7/48, Patanjal Yog Darshan sutra 1/1,2,3and 4/29,30,31 refers).