The Single Eye

In Israel's day there was unjudged evil among them and the eye and heart were not single. So they were told to "put away the strange gods and Ashtaroth," and also to "serve Him I the Lord] only." So now there are "strange gods": some things occupying the heart contrary to the truth, something between the soul and the Lord. It may be the world, its pride, wealth, honor, or pleasure in some shape or other. Or it may be pet lusts, self-love, self-exaltation, or something else cherished or allowed which the Word of God positively condemns.
If this be so, the eye cannot be single, nor the heart only desiring the glory of God-serving Him only. The affections are not set on heavenly things. The eye and heart are not exercised in the life and walk of faith, and things of time and sense so occupy the soul that there is desire to have, rather than present possession and enjoyment. So, like Israel of old, they go on year after year lamenting after the Lord (1 Sam. 7:2, 3).