+I. Here is an exhortation to Christian fortitude.+--"Be strong in
the Lord, and in the power of His might." It is not bodily but mental
strength which is here intended. True fortitude or courage is a
temper of mind by which we steadily follow the calls of duty, without
being deterred by danger or diverted by difficulty. It is a virtue
founded in a regard to God and supported by faith in Him. It is cool
and deliberate, not rash and impetuous; it is kind and compassionate,
not cruel and revengeful; it is steady and patient, not fickle and
inconstant; it continues in well-doing, persuaded that its labour is
not in vain.
+II. A warning against the enemies to be opposed.+--The apostle
mentions two sorts of enemies.
1. _The first he calls flesh and blood._--The motions of our animal
nature. The phrase may further intend those sensible objects which
are suited to gratify fleshly desires; or it may intend mankind, who
are partakers of flesh and blood.
2. _The other kind of enemies with whom we are to contend are evil
spirits._--These spirits are enemies to mankind. Their number is
great, and the terms used denote a subordination among them. They are
not divided against themselves, but act in concert under the
direction of one leading spirit, who is called the devil and Satan.
They have great power over such as submit to their dominion. Their
chief influence is over the ignorant and superstitious. They most
successfully carry on their designs in the dark. When the Gospel
began to shine, Satan began to fall. Among those who reject the
Gospel he recovers his full dominion.--_Lathrop._