John 21:11 Simon Peter went up, and drew the net to land full of great fishes, an hundred and fifty and three: and for all there were so many, yet was not the net broken. 

I always thought it was a bit odd that John mentioned such an exact number of fish. But he was a fisherman and maybe this was his epic fishing story.

But it turns out 153 has a special feature. It is called a triangular number. 17+16+15+14+13+12+11+10+9+8+7+6+5+4+3+2+1=153.

This s a good number if you're trying to show a big pile. Imagine a pyramid with a base of 17 piled all the way up to the one on the peak.

The gematria comes into play when we look at this verse from Ezekiel about waters emanating from the temple:

Ezekiel 47:10  And it shall come to pass, that the fishers shall stand upon it from En-gedi even unto En-eglaim; they shall be a place to spread forth nets; their fish shall be according to their kinds, as the fish of the great sea, exceeding many.

In Hebrew "en" means spring and "gedi" means goat and "eglaim" means calves.

The gematria of "gedi" is 17

Gimel ג 3

Dalet ד 4

Yod י 10

Total גְּדִי 17 

The gematria of "eglaim" is 153

ע Ayin 70

ג Gimel 3

ל Lamed 30

י Yod 10

ם Mem 40

Total עֶגְלַיִם 153

So by recording the specific number of fish John is able to signal a nod to this prophecy of Ezekiel. It's like he saying that Jesus has fulfilled this prophecy.