Why does God want us to glorify Him?
The Lord’s desire to be glorified is the opposite of man’s desire to be praised. There is no pride in God’s self-exaltation. His goodness and the goodness that He encounters, directly benefits those who are in Him. His joy is our joy and His pain ours. When He is exalted, we are exalted. This is why Jesus uses the word “in” when describing His relationship with the Father instead of “with” (John 14:20). “With” does not adequately express the closeness of God’s intended relationship to us.
Therefore, when the Lord ruthlessly weeds out those who would seek to bring a stain upon His name, He does so not in pure self-interest, but also in the interest of those whom He has reconciled to life in Him. His desire to be glorified contains within it the desire to bless His children more than they could ever imagine.
We know that we cannot make God more glorious. He is by definition, maximally glorious. This proves that He did not create us in order that He might become more glorious. So, when He uses us to glorify Himself, we see that He does so for us, not Him (this might be a point of contention with my reformed friends). He is glorified and we benefit. When He is glorified in us, He is unchanged (He is immutable). When He is glorified in us, we are changed. This does not mean that God needs us for anything. He is maximally great no matter what we do.
Sin and self-exaltation is what warps the human mind into thinking that God’s pursuit of glorification is selfishness much the same way as an unborn child (if he could communicate) would condemn his mother for being selfish as she eats food. The food will nourish both. Sin so enraptures the self upon itself that eyes are made dull and mutual benefit becomes something that only benefits others (in the sinners view) because it does not exclusively benefit oneself.
We elevate ourselves to God’s station and claim all things for ourselves and none for others. The same way the liar before King Solomon agreed to have a baby cut in half. If she could not have the baby, then the true mother couldn’t have her either.
While we are voluntarily in this utterly depraved state, the loving Father stoops down into our slop and dresses us in His glory. God’s glory is grace.