1. Paul's admonition here is designed for those who, having heard the
Gospel and made a fine start in believing, immediately imagine
themselves secure and think they have accomplished all. Forgetful
that they are still flesh and blood, and in the world and in contact
with the devil's kingdom, they live in unconcern, as if delivered
from all danger, and the devil far fled. By the very reason of their
security they are overcome of the devil and their own flesh, and fall
unawares from the Gospel. They have just enough connection with it to
be able to prate of it, boasting themselves Christians but giving no
indication of the fact in their conduct.
2. Paul would tell them how, in view of these things, vigilance is
essential to the Christian life. To regulate the life by keeping
God's will ever before the eyes, always conforming the conduct to
it--this he calls walking circumspectly and being wise. If you for a
moment lose sight of God's will, the devil immediately possesses you
and works pernicious results, transforming a Christian into an
indolent, self-secure hypocrite; a hypocrite into a heretic and
factionist; and a heretic into an open enemy. So the apostle here
teaches that in all seriousness if we would secure ourselves against
the craft and power of the devil we must be vigilant; we must be
careful how we walk. In Satan we have an enemy bent on hindering us;
on undermining our very foundation.
3. Consequently they who fail to keep earnest watch over their
Christian life--that is, to have a care for soundness of belief and
to gladly hear and obey the Word of God--are unwise, even foolish,
and have no knowledge of God's will. They have removed the light from
before their eyes to behold instead a thing of their own imagination.
They see as through a painted glass, presuming they do well in
following such phantoms of their reason, until they are misled and
defeated of the devil.