I. Mankind has been in the position of a child, and successive generations have been slowly trained by God's fatherly care, as a preparation for that liberty wherewith Christ has made us free, that life and immortality brought to light by the Gospel, the all-pervading glory of the Sun of righteousness.
II. Consider the lessons to be learned from the fact that the preparatory discipline of a partial revelation and imperfect religious system in the law has been followed by a complete manifestation of God to man in the Gospel. Throughout the Epistle to the Galatians St. Paul protests against the fatal error of confounding the two dispensations and of viewing the law, not as ordained to make ready the way of the Lord, but as intended to be a permanent rule, entangling us for ever in the yoke of bondage. After that faith is come;faith in Christ as a living Friend and Saviour, whose great love for us constrains us to love Him in return, we are no longer under a schoolmaster,we have no more need of such a tutor, nor would it be natural to submit to such discipline.
III. In reckoning the law among the elements of the unspiritual outer world, St. Paul is only speaking of its transient institutions, its principle of mere obedience to the letter, its temporary permission of imperfect morality, its sacrifices, ceremonies, and types, which were to train mankind for Christianity, and not of its eternal testimony to truth and holiness. (1) We shall fall back under the bondage of the law if we go about to establish our own righteousness, instead of submitting ourselves to the righteousness of God. (2) We return to the law if we content ourselves with a conventional Christianity, a mere conformity to the standard of religion sanctioned by the world. (3) We may also become entangled again in the yoke of bondage by lowering the standard of Christian holiness and adopting some of those inferior principles of morality which, in the times of ignorance, God winked at. (4) Once more, we are falling back, like the Galatians, to the elements of the world if we are led astray, by a formal and ceremonial system of religion, from the simplicity that is in Christ. We Christians are called to the duties and privileges of spiritual manhood, to obedience resulting from principle, from conviction, from gratitude for God's forgiving mercy, and a desire for true holiness. This desire can only be gratified, these feelings can only be realised, through fellowship with the Lord Jesus by faith. Therefore whatsoever keeps us from Him is a return from the brightness of the New Testament to the twilight of the Old.
G. E. L. Cotton, Sermons on the Epistles,vol. i., p. 64.
Reference: Galatians 4:3-6. Spurgeon, Sermons,vol. xxx., No. 1815.