Hey Dre91
These scriptures should point to why:
Luk 11:37 And as he spake, a certain Pharisee besought him to dine with him: and he went in, and sat down to meat.
Luk 11:38 And when the Pharisee saw it, he marvelled that he had not first washed before dinner.
Luk 11:39 And the Lord said unto him, Now do ye Pharisees make clean the outside of the cup and the platter; but your inward part is full of ravening and wickedness.
Mat 23:25 Woe unto you, scribes and Pharisees, hypocrites! for ye make clean the outside of the cup and of the platter, but within they are full of extortion and excess.
Mat 23:26 Thou blind Pharisee, cleanse first that which is within the cup and platter, that the outside of them may be clean also.
Mat 23:27 Woe unto you, scribes and Pharisees, hypocrites! for ye are like unto whited sepulchres, which indeed appear beautiful outward, but are within full of dead men's bones, and of all uncleanness.
Mat 15:17 Do not ye yet understand, that whatsoever entereth in at the mouth goeth into the belly, and is cast out into the draught?
Mat 15:18 But those things which proceed out of the mouth come forth from the heart; and they defile the man.
Mat 15:19 For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies:
Mat 15:20 These are the things which defile a man: but to eat with unwashen hands defileth not a man.
Mat 23:28 Even so ye also outwardly appear righteous unto men, but within ye are full of hypocrisy and iniquity.[/b]
As for where it came from, the same place that causes us to believe that our outward appearance makes us righteous
Hope these help
Antaiwan