Same thing I always say:
Its never 1+1+1=3 (as most muslims assume)
Its 1x1x1=1 (God the Father, God the Son, God the Holy Ghost)
Anyone, including hisway, can quote the OT with the names given to God Almighty. But just as the other brothers have quoted, the NT changed all things. Our new covenant.
I personally believe that Jesus saying "it is complete", meant more than just his sacrifice for the sins of the world. It was also the completion of the Trinity.
Peace and Godspeed
Pray for Isreal