J.C. Ryle, Holiness, Moody Publishers, 2010, p. 113-114.
[The devil] is always “going about as a lion seeking whom he may devour.” An unseen enemy, he is always near us, about our path and about our bed, and spying out all our ways. A “murderer and a liar” from the beginning, he labors night and day to cast us down to hell. Sometimes by leading into superstition, sometimes by suggesting infidelity, sometimes by one kind of tactics and sometimes by another, he is always carrying on a campaign against our souls… The strong man armed will never be kept out of our hearts without a daily battle.
J.C. Ryle, Holiness, Moody Publishers, 2010, p. 113-114.