Strangers have devoured his strength - from Hosea 7:9
What gives spiritual weakness like allowed sin? It was so with Israel, it will ever be so with us. Yielding to unhallowed association (with) strangers devour our strength.
If you ever saw a cake not turned, baked only on one side, of what use is it? Of what use is a worldly, backsliding Christian?
"Strangers have devoured his strength" tells of the powerlessness of one under sin. The order is, first, at conversion, God takes us up out of this present evil age; and then next, sends us into it. Not to be of it, but to be lights in it, and to take others out of it.
"The friendship of the world is enmity to God." It is like the ivy with the oak (tree), the ivy may give the oak a grand, beautiful appearance, but all the while it is feeding on the vitals.
The next image tells of the result. Ephraim is like a silly dove, without heart "some read with but one wing," and so unable to fly. Thus where sin is, there is no power to rise and get out of danger.
It is proverbial of doves, that when any surprise or sudden alarm comes upon them they are without heart and have no strength so that instead of fleeing from danger, they seem hopelessly to fall into it. - J. D. S.
---a classic illustration by D. L. Moody