1 Samuel 16:7
7 But the LORD said to Samuel, "Do not consider his appearance or his height, for I have rejected him. The LORD does not look at the things people look at. People look at the outward appearance, but the LORD looks at the heart."
I believe our words and the tone we use are very important.
Leviticus 19:11
11 Ye shall not steal, neither deal falsely, neither lie one to another.
12 And ye shall not swear by my name falsely, neither shalt thou profane the name of thy God: I
am the LORD.
Ephesians 4:25
Wherefore putting away lying, speak every man truth with his neighbour: for we are members one of another.
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.
Ephesians 5:4
Neither filthiness, nor foolish talking, nor jesting, which are not convenient: but rather giving of thanks.
Colossians 3:8
But now ye also put off all these; anger, wrath, malice, blasphemy, filthy communication out of your mouth.
And it may take us a lifetime to learn to always think before we speak.