"Nay but, O man, who art thou that repliest against God? Shall the thing formed say to him that formed it, Why hast thou made me thus?" ( Rom. 9:20)
“Who do you think you are?” That's what God is saying. It's easy to forget sometimes that God is God, and we're not. There would not even be a "we" were it not for Him. When we murmur and complain about our lot in life, our appearance, or our inherent weaknesses, we question the wisdom of God Almighty, in the way He formed us. Even worse, we question His love. Those things we consider strikes against us are really advantages for seeing and experiencing the presence and power of God. They are what make us who we are. Common sense would tell you not to second guess your Creator.
"Who art thou that judgest another man's servant? to his own master he standeth or falleth..." (Rom. 14:4)
Again, “Who do you think you are? This time, not by questioning the way God deals with us, but questioning, and attempting to meddle in, the lives of others. Too often we feel that we know God's will for someone else and are obligated to share it with them! It's one thing to offer general, Scriptural advice, when solicited; it is quite another thing, however, to mark out a path for someone else, claiming Divine authority. Worse still would be to question the sincerity of someone who is following what he or she deems to be the will of God for his or her life. Unless unquestionable sin is involved, we have no authority to judge "another man's servant."
Here then are two good rules to follow:
1) Never question God's working in your own life.
2) Never question God's working in the life of another.
And the next time you're tempted to do either, remember God's question to you: "WHO DO YOU THINK YOU ARE?"