"Thou shalt not take The Name of THE LORD thy GOD in vain; for THE LORD will not hold him guiltless that taketh HIS NAME in vain." Exodus 20:7
"I said, I will take heed to my ways,that I sin not with my tongue; I will keep my mouth with a bridle while the wicked is before me." Psalms 39:1
"Let the words of my mouth and the meditations of my heart be acceptable in THY sight O LORD, my strength and my Redeemer." Psalms 19: 14
"The wicked is snared by the transgression of his lips; but the just shall come
out of trouble. . . he that speaketh truth sheweth forth righteousness but a false witness deceit. There is that speaketh like the piercings of a sword, but the tongue of the wise is health. The lip of truth is established forever, but a lying tongue is but for a moment. Deceit is in the heart of them that imagine evil; but to the counsellors of peace is joy. There shall no evil happen to the just; but the wicked shall be filled with mischief. Lying lips are abomination to THE LORD; but they that deal truly are HIS delight. " Proverbs 12: 13,17-22
"The words of a wise man's mouth is gracious but the lips of a fool will swallow up himself. The beginning of the words of his mouth is foolishness and the end of his talk is mischievous madness A fool is full of words; a man cannot tell what shall be; and what shall be after him, who can tell? . . . curse not. . . "
Ecclesiastes 10: 12-14,20a
"A soft answer turneth away wrath, but grievous words stir up anger. The tongue of the wise useth knowledge aright; but the mouth of fools poureth out foolishness. . . a wholesome tongue is a tree of life; but perverseness therein is a breach of the spirit. . . the lips of the wise disperse knowledge but the heart of the foolish doeth not so. The sacrifice of the wicked is an abomination to THE LORD, but the prayer of the upright is HIS delight. . . a man hath joy by the answer of his mouth; and a word spoken in due season, how good it is!. . . the thoughts of the wicked are abomination to THE LORD but the words of the pure are pleasant words. . . the heart of the righteous studieth to answer, but the mouth of the wicked poureth out evil things. THE LORD is far from the wicked, but HE heareth the prayer of the righteous. " Proverbs 1, 2,4,7,8,23,26,28,29
"The heart of the wise teacheth his mouth, and addeth learning to his lips.Pleasant words are as an honeycomb, sweet to the soul, and health to the bones." Proverbs 16:23-24
"Be not rash with thy mouth, and let not thine heart be hasty to utter any thing before GOD , for GOD is in heaven, and thou upon earth; let therefore thy words be few. . .for a dream cometh through a multitude of business, and a fool's voice is known by a multitude of words. When thou vowest a vow unto GOD defer not to pay it; for HE hath no pleasure in fools; pay that thou hast vowed.. . Suffer not thy mouth to cause thy flesh to sin; neither say thou before The Angel that is wss an error, wherefore should GOD be angry at thy voice? and destroy the work of thine hands? For in the multitude of dreams and many words there are also divers[e] vanities; but fear thou GOD." Ecclesiastes 5:2,3,4,6,7
"All the while my breath is in me and the spirit of GOD is in my nostrils, my lips shall not speak wickedness nor my tongue utter deceit. " Job 27: 3-4
"The transgression of the wicked saith within my heart, that there is no fear of GOD before his eyes. For he flattereth himself in his own eyes, until his iniquity be found to be hateful. The words of his mouth are iniquity and deceit; he hath left off to be wise, and to do good. He deviseth mischief upon his bed; he setteth himself in a way that is not good, he abhorreth not evil. . . let not the foot of pride come against me and let not the hand of the wicked remove me."
Psalms 36: 1-3,11,12
"Keep thy tongue from evil and thy lips from speaking guile; depart from evil,and do good, seek peace and pursue it. The eyes of THE LORD are upon the righteous and HIS ears are open unto their cry. The face of THE LORD is against them that do evil, to cut off the remembrance of them from the earth." Psalms 34:13-16
JESUS said, "a good man out of the good treasure of his heart, bringeth forth good things, and an evil man out of the evil treasure bringeth forth evil things. But I say unto you, that every idle word that men speak, they shall give an account thereof in the Day of Judgement; for by thy words thou shalt be justified and by thy words thou shalt be condemned." Matthew 12: 35-37
"And now ye also put off all these: anger, wrath, malice, blasphemy, filthy communications out of your mouth. Lie not to one another, seeing ye have put off the old man with his deeds." Colossians 3: 8-9
JESUS said, "ye hypocrites! well did Esaias {Isaiah} prophesy of you, saying, this people draweth nigh unto ME with their mouth, and honoureth ME with their lips but their heart is far from ME. But in vain do they worship ME, teaching for doctrines the commandments of men.' And HE called the multitude and said unto them, 'hear and understand. Not that which goeth into the mouth defileth a man,but that which cometh out of the mouth, this defileth a man."Matthew 15: 7-11 and then repeated, "do not ye yet understand? That which entereth in at the mouth, goeth into the belly and is cast into the draught? But those things which proceed out of the mouth come forth from the heart, and they defile the man. For out of the heart, proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies; these are the things which defile a ma; but to eat with unwashen hands, defileth not a man." Matthew 15:17-20.
[I am adding a note here to that paragraph that I understand this to mean that though unwashed hands may cause germs and maybe sickness, they do not prevent you from going to heaven or hell; but what is in your heart toward GOD and HIS Commandments and Word, and whether you submit to GOD, recognize HIS Sovereignty over you, confess HIM as LORD over your life, those are the attitudes and deeds that decide whether you go to heaven or to hell, i.e. whether you are defiled or pure.]