The multitude following Jesus was spellbound. He spoke in a manner they had never heard. For example:
"Before Abraham was I am...", John 8:58. -- "I and my father are one.", John 10:30. -- "...he that hath seen me hath seen the father...", John 14:9. -- "...I will come again, and receive you unto myself...", John 14:1-3. -- "Verily, Verily, I say unto you, He that believeth on me hath ever lasting life.", John 6:47. -- “It is finished.”John 19:30.
These theological statements are absolutely necessary in our understanding of who Jesus Christ really is. “It is finished.” (I believe) are the greatest words Jesus ever uttered.
John 19:30 When Jesus therefore had received the vinegar, he said, “ It is finished.” and he bowed his head, and gave up the ghost.
Because "It is finished", you and I can enjoy salvation through the blood of Jesus without having to fear that our works aren't good enough.
Because “It is finished”, we can enjoy fellowship with the Father, knowing He will accept us because we have accepted His Son. Only believe.