Because "three days and three nights " is literal, but This "IS" my body is a metaphor.
Yes, his body IS the temple,
He is the Word made flesh on the Earth, the temple made of stone in Jerusalem was nothing but a shadow of a future promise made manifest in the Earth with the Holy Laws and Ordinances which he fulfilled and stood right in front of them knowing they did not understand those same words, and he arrived with the promise of so prophetic a fulfillment, that Israel was held accountable for not knowing it and their house was left desolate until he ‘yet chooses them again’ at the close of the age,
‘When the Lord shall build up Zion, he will appear in his Glory’ - Psalm 102
The timing element in Daniel Chapter 9 was so direct, so powerful and so precise that Gabriel was blocked by Satan for 21 days before he could deliver this information. Why did Satan fight so hard to prevent this, because he knew that once it became scripture (that is that Daniel records this information as a Prophet of Israel) that ‘not one jot or tittle’ could be moved later,
Jesus now sits at the right hand of the father [until] he makes the Kingdoms of this world his footstool, which is whats occurring in Revelation Chapters 4, 5 and 6. The court is in session deliberating over the ownership of the Earth as the timing mechanism under the law enacted on the Earth (the Jubilee) is being completed, (with the fullness of the Gentiles)