'Of the Flesh' in the Bible

Ye know how though infirmity of the flesh, I preached the gospel to you at first.

I say then, walk by the Spirit, and fulfil not the desire of the flesh.

Now the works of the flesh are manifest, which are these, adultery, fornication,

For he that soweth to the flesh, shall of the flesh reap corruption; but he that soweth to the Spirit, shall of the Spirit reap life everlasting.