When people consciously try to prove themselves, they turn inward focused.
Trying to build a reputation for oneself can actually lead to self-glorification. Not that it is wrong to want a good reputation, but if you find yourself going out of your way, there may be some self-esteem issues involved. Trying to prove to others that you are something, whether you are or not, can actually detract from your true self. Ironically, those seeking to prove themselves tend to look disingenuous. It comes across like they are not who they say they are, even if they are legitimate. Others don't see the real them; they see a hypocrite. Trying to prove ourselves can be hard work, and leads to undue pressure. Instead of enjoying the freedom found in Christ Jesus, we can walk on eggshells, worrying about what others think. This leads to second-guessing ourselves, or perhaps doing things that are unnecessary.
For example, if you try to prove to someone that you love him or her, it would be possible to step away from pure love.
This is especially true if proving is the emphasis, and not love itself. Pure love takes joy in the recipient for the recipient's sake alone. It's outward focused, and not so concerned with how one looks to another. So yes, it is a very good thing to give someone a token of your esteem when it's the result of your love. “The proof will be in the pudding.” When you genuinely love another, the other will know it. Sure, he or she may take a while to catch on, even when you tell him or her. Nonetheless, when you shift from simply loving people to proving it, it becomes “all eyes on me.” Basically, you become more concerned about yourself than you are about them. In fact, you may actually become preoccupied about whether they love you in return. This may be a question to ask: “Am I actually seeking their love and approval?” Without realizing it, some do things for others in order to gain their acceptance. It's one thing to see a smile on another person's face, because he or she was just blessed by you. It's another when you need the pat on the back in return. Not that the pat on the back is a bad thing, but when you do things to get it, you're no longer doing it purely for them. This is not intended to get you to question your motives every time you do something for someone else. The point is that it can be easy to turn from affirming others to seeking their affirmation instead.
Those who don't want to look bad will try to do things to make themselves look good. If you don't want people to think you're a bad person, be who God called you to be. Even that may have some ramifications. Jesus said, “If the world hates you, you know that it has hated Me before it hated you. 19. If you were of the world, the world would love its own; but because you are not of the world, but I chose you out of the world, because of this the world hates you. 20. Remember the word that I said to you, 'A slave is not greater than his master.' If they persecuted Me, they will also persecute you; if they kept My word, they will keep yours also. 21. But all these things they will do to you for My name's sake, because they do not know the One who sent Me” (John 15:18-21, NASB). That means not everyone is going to think highly of you, no matter how Christlike you may be.
Where in the Bible does it say we are to prove ourselves?
It does talk a lot about God proving us. Why is this important? For one thing, if we don't have an accurate picture of ourselves, we would gravitate toward trying to be who we are not in the eyes of God. That leads to phoniness. When the Lord tries us, He is taking us through a process to become who He destined us to be. In short, God says who we are and who we are meant to be, then proves it. This is where the trying of our faith comes into play. He will use His proving process to eliminate anything in us that is contrary to His nature. The method of our crucifixion is best left in His hands. 1 Peter 1:6-7 In this you greatly rejoice, even though now for a little while, if necessary, you have been distressed by various trials, 7. so that the proof of your faith, being more precious than gold which is perishable, even though tested by fire, may be found to result in praise and glory and honor at the revelation of Jesus Christ (NASB).
Another pitfall to all this is pride.
Has anyone ever challenged you? You know, “Prove it!” What was your response? Did you feel pride welling up? Has anyone ever called you a hypocrite? If so, did you find the need to prove him or her wrong? One of the ways the enemy seeks to get us to succumb to pride is by attacking our identity. He tried it with Jesus. Matthew 4:3And the tempter came and said to Him, "If You are the Son of God, command that these stones become bread." (NASB). Jesus didn't try to prove it, He knew who He was, which means He didn't have to prove anything. In fact, He humbled Himself by responding with the Word of God. When you know who you are in Christ Jesus, you won't feel the need to prove you are a son or daughter of God. On the other hand, if you fail to believe what the Father says about you, you will find yourself seeking affirmation.
Being proved is a patience game, if you will. Using our previous example, when you want others to know you love them, so they may feel affirmed by you, you will have to let time take its course. Eventually, they will figure it out. Beware that there are those who struggle with receiving love, so some may require more patience than others. However, that's another lesson in itself. People don't need to wear a t-shirt to let others know they are believers. Others will know they're believers by their fruit.
Proverbs 22:1A good name is to be more desired than great wealth, Favor is better than silver and gold (NASB). Consider this, if you have Jesus, you have the Name above all names. Would it better to glorify His than to try to build up ours? When we seek to glorify God, everything else falls into place.