Observe with attention!

I was reading Isaiah 41 - 47 last night, and if you do have the time, you can count how many times our God repeated over and over again with this word :"I AM GOD, I AM the LORD, I AM HE ......" Why HE need to repeat so many times? as the above word says : "Observe with attention". And if you were to "observe with attention", you will realized that we always turn to ourselves saying : "i am able. i can......", but all that bring is cares and worry, isn't it?
I remember a hymn which says: "At the cross, at the cross when i first saw the light and the burden of my heart rolled away, it was there by faith, i received my sight, and now i am happy all the way." Our Lord said "It is finished", do you understand what did the Lord had done for all of us, what i have to say is "Go, go and observe with attention what our Good Lord has done for us." Be Blessed !.