Faith is not required... Your response to this subject is flawed... Of course it is impossible to obey perfectly. Every parent knows this. But when a sin is committed God provided forgiveness. When your child sins the first time do you immediately condemn him or her?
Also "Kiss the son" is not a valid translation of the Hebrew "Bar Nesqu". It actually means "Embrace purity". Bar is Aramaic not Hebrew for son (Hebrew is "ben".) There is no Aramaic in the Psalms only Hebrew. I am sorry but your arguments are in error.