Matter of fact, Jesus explains Himself right in John 3:5, “Jesus answered: Amen, amen I say to thee, unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God.” Both John 3 and John 6 have this in common: a startling statement is meant by Jesus, the unbeliever asks to clarify, and Jesus does. In John 3 He explains that the second birth is baptism, in John 6 that His flesh is “food indeed”. Further, in both cases Jesus insists on the sacramental character of baptism and of the Eucharist: they are what they signify, water gives a rebirth and His flesh quickens the spirit. In neither John 3 or John 6 Jesus says “eh, I only meant it symbolically”.
I guess I don't know how to respond to that.
So, 'born again' = 'baptism' -- no symbolism involved...
I was hoping that Matt 19:21 was using symbolism...