Out of your mouth flows the issues found in your heart. So many of those issues can be minimized or stopped before they begin, by controlling the thoughts surrounding them. Because the Word teaches that "as he thinks in his heart, so is he," we then know that those thoughts can manifest into the physical realm simply by dwelling on them. Our very rehearsal of thoughts, good or evil, are the fertilizer those thoughts need to germinate, and ultimately come to fruition, that is, bear fruit.
2 Corinthians 10:3-6 says: We are human, but we don’t wage war as humans do. We use God’s mighty weapons, not worldly weapons, to knock down the strongholds of human reasoning and to destroy false arguments. We destroy every proud obstacle that keeps people from knowing God. We capture their rebellious thoughts and teach them to obey Christ. And after you have become fully obedient, we will punish everyone who remains disobedient.
Today's societal thinking veers towards the fulfillment and buoying of "me," everything is about "me" and what "I" can do to become a better "me" by doing things to bolster more of "me." Self-help, self-realization, self-actualization, and on and on. Yoga, meditation, chanting, all of those self-absorbing practices can be dangerous to the soul seeking a deeper relationship with Jesus Christ. They can be soothing and healing, but can also become a subtle distraction from focusing on God to focusing on self. Those are the thoughts that need to be captured and disciplined toward the living for God. There is nothing wrong with seeking betterment of oneself, as long as it doesn't dethrone God. God wants us to prosper as our souls prosper, so He wants us to be better, but not at the expense of our souls (from where our thoughts originate).
Capturing our thoughts and keeping them captive to the obedience of Christ is the way to discipline our thoughts. Whenever an errant thought crosses our mind, immediately redirect it onto the straight and narrow, or else it will take a detour from the planned route. Ever wonder "how did I get here?" Often it's because of unplanned and uncontrolled detours. Some detours are unplanned, but they do not have to be uncontrolled. Keep the goal in mind and get back to the planned route and "train of thought" as soon as possible, or you could end up so very far away from the goal. Being disciplined takes practice, it is not an overnight successful accomplishment, and it is ongoing, not a one-time deed.
Different distractions and modes of thought will constantly bombard us, and it's up to us to recognize them for what they are the moment they enter our sphere. Some thoughts are meant to open a closed mind, which is good, but if taken too far, open it to...what? Some forms of meditation are for soothing frayed nerves and smoothing jagged edges, which is wonderful, but if not researched in origin and mode, you meditate on...what?
Again, before we seek to discipline anyone or anything other than ourselves, we need to discipline our own thoughts.