What you think about you bring about

“For those who live according to the flesh set their minds on the things of the flesh, but those who live according to the Spirit set their minds on the things of the Spirit. For to set the mind on the flesh is death, but to set the mind on the Spirit is life and peace.” (Rom. 8:5-6 ESV)

We choose what we set our minds on

The above passage says we can choose to set our minds on things of the flesh (carnal things) or things of the Spirit (Spiritual things). One leads to death and one leads to life, and we personally decide which one we set our minds on.

Be transformed by renewing your mind

“Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.” (Rom. 12:2 ESV)

Take your thoughts captive to obey Christ

“We destroy arguments and every lofty opinion raised against the knowledge of God, and take every thought captive to obey Christ.” (2 Cor. 10:5 ESV) 

Think about these things

“Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things.” (Phil. 4:8 ESV)

Therefore

“Keep your heart with all vigilance, for from it flow the springs of life.” (Prov. 4:23 ESV)