Note: All Scripture quotations found in this article are from the text of the Authorized King James Version of the Bible.
For the lost, they will have to give account of every idle word at the White Throne Judgment, which is the last judgment (Revelation 20:11). The below verse is good spiritual application to the Christian though. God expects the Christian to live a holy life, so as Christians we should not curse, nor use filthy language because it hurts our fellowship with God and ruins our testimony.
Matthew 12:36 "But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment. 37 For by thy words thou shalt be justified, and by thy words thou shalt be condemned."
Christians should have a pattern of good works. Sound speech will line up with the word of God. This means we should not teach false doctrine, nor use language that is against God. Let your conversation be as the oracles of God. Whatever we say should give glory to God and be the truth.
Titus 2:7 "In all things shewing thyself a pattern of good works: in doctrine shewing uncorruptness, gravity, sincerity, 8 Sound speech, that cannot be condemned; that he that is of the contrary part may be ashamed, having no evil thing to say of you."
1 Peter 4:11 "If any man speak, let him speak as the oracles of God; if any man minister, let him do it as of the ability which God giveth: that God in all things may be glorified through Jesus Christ, to whom be praise and dominion for ever and ever. Amen."
We are commanded not to swear. Saying "oh my God", "oh my heavens", "oh my lands", "oh my stars" and etc is a sin. We should respect the holy name of God and his words and not disgrace them (Matthew 6:9, Exodus 20:7). Our conversation should be yes or no, not evil.
Matthew 5:34 "But I say unto you, Swear not at all; neither by heaven; for it is God's throne: 35 Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. 36 Neither shalt thou swear by thy head, because thou canst not make one hair white or black. 37 But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil."
No corrupt communication should come out of our mouths. Corrupt communication can be cursing, dirty jokes, slander, rumors or anything filthy. Our words should edify and bless other believers and minister to the lost. Everything we say should glorify God and proclaim the gospel of Jesus Christ.
Ephesians 4:29 "Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers."
Philippians 1:27 "Only let your conversation be as it becometh the gospel of Christ: that whether I come and see you, or else be absent, I may hear of your affairs, that ye stand fast in one spirit, with one mind striving together for the faith of the gospel;"
James 3:9 "Therewith bless we God, even the Father; and therewith curse we men, which are made after the similitude of God. 10 Out of the same mouth proceedeth blessing and cursing. My brethren, these things ought not so to be."
God judges the length of our life by how we use it, so we should watch what we say and not speak guile or evil things.
1 Peter 3:10 "For he that will love life, and see good days, let him refrain his tongue from evil, and his lips that they speak no guile:"
Proverbs 21:23 "Whoso keepeth his mouth and his tongue keepeth his soul from troubles."