Do not be anxious about anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus. Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things. Whatever you have learned or received or heard from me, or seen in me—put it into practice. And the God of peace will be with you. Philippians 4:6-9

We control our mind. Our mind has a door and we are the gate keeper. Negative thoughts arrive at our door and we must decide whether we are going to allow them in, have a seat and stay awhile or are we going to tell them “You’re not welcomed here” and slam the door in their face.

Negative thoughts could come from Satan, tempting us to sin or lose our faith in God. Negative thoughts could come from habit, since our minds have been trained to always think that these kinds of things will always fail. Negative thoughts could come from others, friends or family who act like Debbie Downer and spoil any hope of hope.

Negative thoughts could come from God, if they are warnings of impending doom, as he spoke to the prophets. The purpose of those thoughts, though, are to help us evade destruction while negative thoughts from other sources are meant to tear us down.

Use discernment with every negative thought.  Don't accept it as truth too quickly.