Just the phrase "Body building" shows its intent. Who are you building your body for? Advancement of self? "Hey look at me!"
We are called not to build our bodies, but our souls. That our "souls might be built up in the most holy faith" should be the aim of the believer.
That doesn't mean to neglect our bodies. Scriptures doesn't say bodily exercise is worthless, but it does say "For bodily exercise profiteth little: but godliness is profitable unto all things, having promise of the life that now is, and of that which is to come." (1 Tim. 4:8).
There is some little profit to bodily exercise but it should be viewed as that which keeps us fit, that we may follow after godliness.

__________________
Sterling Harmon
Coventry, CT
PCA
Deacon
________________
"Whatever is laudable in our works proceeds from the grace of God."
--
John Calvin, Institutes III:xv.3.
"Our Lord God must be a good man, to be fond of worthless fellows. I cannot like them, and yet I, myself, am one."
--
Martin Luther, Table Talk