1 Samuel 18:5 So David went out wherever Saul sent him, and behaved wisely
1 Samuel 18:14 And David behaved wisely in all his ways and the Lord was with him.
1 Samuel 18:15 Saul saw that David behaved very wisely
1 Samuel 18:30 David behaved more wisely than all the servants of Saul.
Following his victory over Goliath, David was given the great privilege of being King Saul's armor bearer and the head of the men of war. This promotion was something that David took very seriously. Four times within the chapter it says he "behaved wisely". Regardless of what task he was given David carried himself in a manner that honored the Lord. The chapter also records the results of his behavior. In verse five it says "David was accepted in the eyes of the people and Saul's servants." One thing I love about David is he didn't try to be something he wasn't. He did his job as unto the Lord and he was accepted. One of the greatest blessings bestowed on David is found in verse 14 when it says, "The Lord was with him." David had the daily assurance of God's presence. Knowing God is with you wherever you go makes all the difference in the world. David continued to grow as an armor bearer and a leader among God's people. I wish that David's behavior resulted only in positive feedback, however that was not the case. Not everyone was pleased with him. King Saul's heart began to grow bitter toward David. The people were singing songs about David having more victories than Saul. Filled with envy, Saul picked up his spear and tried to pin David to the wall. He also incited his servants to ensnare David. The Bible says that Saul was motivated by fear and became David's enemy continually. Nevertheless David continued to behave wisely.
There may come a time when you are in a circumstance where you can choose to behave wisely or react harshly. You can wait patiently or get even immediately. It's always best to let the Lord fight your battles. Remember that the Lord is with you. Continue to live your life on the job, at school, at home, or at your church; that pleases God.