Ephesians 5:17

Wherefore be ye not unwise, but understanding what the will of the Lord is.

Therefore don't be foolish, but understand what the will of the Lord is.

Wherefore be ye not foolish, but understand what the will of the Lord is.

because of this become not fools, but -- understanding what `is' the will of the Lord,

Therefore do not be foolish, but understand what the Lord’s will is.