"Let the words of my mouth, and the meditation of my heart, be acceptable in thy sight, O LORD, my strength, and my redeemer." Psalm 19:14
Our words and our thoughts are very closely related. One affects the other. Our thoughts affect our words and our words affect our thoughts. Therefore, we must pay attention to what we think about and listen to what we are saying.
This is why we must continually renew our minds and change our thoughts-- our way of thinking. When we do, it will affect our speech. But it is important what we renew our minds with. We can't just renew them with anything. A lot of people are. They are renewing their way of thinking with philosophies, culture, teachings of some religious leader, cultish beliefs, the mindset of society, and so on. What we must renew our minds with is the Word of God. When we do, we are renewing it with truth. We are renewing it with words of life. We are renewing it with God-centered and others centered thoughts and getting away from self-centered thoughts. Once our minds are renewed with God's Word and our thoughts are transformed, our words won't be so negative, condemning, criticizing, full of doubt, fear and unbelief. They will be full of encouragement, hope, faith, grace, kindness, gentleness, truth and life.
So, think about it-- what do you think about? What do you say? One is an indication of the other. What you say comes from what you think. And what you think is influenced by what you say.
Have a great day. Your thoughts and your words affect each other.