That is not the case, holiness is actually the fruit of salvation. Because without it no man shall see the Lord. After the law paul has urged us to present our bodies as a living sacrifice, holy, acceptable unto God which indeed is a very reasonable service.
Some religions ask great sacrifices, and put heavy burdens on their followers.
But our God is not a cruel taskmaster. If holiness was unattainable, he would not have asked it of us. Moreover he has given us his Holy Spirit to help us obtain it. Holy means separated and cleansed from filthiness of the flesh and spirit in order to serve God, It is not self-righteousness. Holiness is not a burden, but a privilege given to a chosen generation, a royal priesthood, an holy nation, a peculiar people.