Romans 12
1Therefore, I urge you, brothers, in view of God's mercy, to offer your bodies as living sacrifices, holy and pleasing to God—this is your spiritual[a] act of worship. 2Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is—his good, pleasing and perfect will.
I BESEECH you... that ye present your bodies a living sacrifice unto God... AND THAT YE BE TRANSFORMED BY THE RENEWING OF YOUR MIND, THAT HE MAY PROVE (experience) what it is to have working in you continually, the good and acceptable and perfect will of God" (Romans 12:1, 2)

"We must allow the Holy Spirit to reveal to each one of us individually the things which He knows... must be cut off altogether from our lives. We dare not touch or use them any longer... The simple fact of saying anything has the real effect of binding that thing in our thoughts. I have found that it is no use to pray to be kept from thinking wrongly unless at the same time I am willing to have all my words censored by the Holy Spirit also. But as soon as I agree with the law of holy Love, and the first time I begin to practice this by refusing to utter the wrong kind if word or sentence-- that moment the thought victory begins. And every refusal and thrusting back of the wrong speaking, means deliverance from the wrong thinking....
The vow that by God's grace and power, we will never again utter a criticizing or disparaging or unkind or unloving remark about anyone else...
No exceptions whatever!!!!!!!...
This first key is so important I think I really must reiterate and re-emphasize...
For the interplay and connection between thought and some expression of the thought is so inseparable, that every expression by word of mouth impresses the thought more deeply on the mind, so that one simply cannot stop thinking about the things one speaks about." (Winged Life Chapter 6 Hannah Hurnard)