Christ's discourse in these verses shows two things: -

I.What is the sign we may expect from God for the confirmation of our faith. The great and most convincing proof of Christ's being sent of God, and which they were yet to wait for, after the many signs that had been given them, was the resurrection of Christ from the dead. Here is,

1.A reproof to the people for demanding other signs than what had already been given them in great plenty: The people were gathered thickly together (Luk 11:29), a vast crowd of them, expecting not so much to have their consciences informed by the doctrine of Christ as to have their curiosity gratified by his miracles. Christ knew what brought such a multitude together; they came seeking a sign, they came to gaze, to have something to talk of when they went home; and it is an evil generation which nothing will awaken and convince, no, not the most sensible demonstrations of divine power and goodness.

2.A promise that yet there should be one sign more given them, different from any that had yet been given them, even the sign of Jonas the prophet, which in Matthew is explained as meaning the resurrection of Christ. As Jonas being cast into the sea, and lying there three days, and then coming up alive and preaching repentance to the Ninevites, was a sign to them, upon which they turned from their evil way, so shall the death and resurrection of Christ, and the preaching of his gospel immediately after to the Gentile world, be the last warning to the Jewish nation. If they be provoked to a holy jealousy by this, well and good; but, if this do not work upon them, let them look for nothing but utter ruin: The Son of Man shall be a sign to this generation (Luk 11:30), a sign speaking to them, though a sign spoken against by them.

3.A warning to them to improve this sign; for it was at their peril if they did not. (1.) The queen of Sheba would rise up in judgment against them, and condemn their unbelief, Luk 11:31. She was a stranger to the commonwealth of Israel, and yet so readily gave credit to the report she heard of the glories of a king of Israel, that, notwithstanding the prejudices we are apt to conceive against foreigners, she came from the uttermost parts of the earth to hear his wisdom, not only to satisfy her curiosity, but to inform her mind, especially in the knowledge of the true God and his worship, which is upon record, to her honour; and, behold, a greater than Solomon in here, pleion Solomōntos - more than a Solomon is here; that is, says Dr. Hammond, more of wisdom and more heavenly divine doctrine than ever was in all Solomon's words or writings; and yet these wretched Jews will give no manner of regard to what Christ says to them, though he be in the midst of them. (2.) The Ninevites would rise up in judgment against them, and condemn their impenitency (Luk 11:32): They repented at the preaching of Jonas; but here is preaching which far exceeds that of Jonas, is more powerful and awakening, and threatens a much sorer ruin than that of Nineveh, and yet none are startled by it, to turn from their evil way, as the Ninevites did.

II.What is the sign that God expects from us for the evidencing of our faith, and that is the serious practice of that religion which we profess to believe, and a readiness to entertain all divine truths, when brought to us in their proper evidence. Now observe,

1.They had the light with all the advantage they could desire. For God, having lighted the candle of the gospel, did not put it in a secret place, or under a bushel; Christ did not preach in corners. The apostles were ordered to preach the gospel to every creature; and both Christ and his ministers, Wisdom and her maidens, cry in the chief places of concourse, Luk 11:33. It is a great privilege that the light of the gospel is put on a candlestick, so that all that come in may see it, and may see by it where they are and whither they are going, and what is the true, and sure, and only way to happiness.

2.Having the light, their concern was to have the sight, or else to what purpose had they the light? Be the object ever so clear, if the organ be not right, we are never the better: The light of the body is the eye (Luk 11:34), which receives the light of the candle when it is brought into the room. So the light of the soul is the understanding and judgment, and its power of discerning between good and evil, truth and falsehood. Now, according as this is, so the light of divine revelation is to us, and our benefit by it; it is a savour of life unto life, or of death unto death. (1.) If this eye of the soul be single, if it see clear, see things as they are, and judge impartially concerning them, if it aim at truth only, and seek it for its own sake, and have not any sinister by - looks and intentions, the whole body, that is, the whole soul, is full of light, it receives and entertains the gospel, which will bring along with it into the soul both knowledge and joy. This denotes the same thing with that of the good ground, receiving the word and understanding it. If our understanding admits the gospel in its full light, it fills the soul, and it has enough to fill it. And if the soul be thus filled with the light of the gospel, having no part dark, - if all its powers and faculties be subjected to the government and influence of the gospel, and none left unsanctified, - then the whole soul shall be full of light, full of holiness and comfort. It was darkness itself, but now light in the Lord, as when the bright shining of a candle doth give thee light, Luk 11:36. Note, The gospel will come into those souls whose doors and windows are thrown open to receive it; and where it comes it will bring light with it. But, (2.) If the eye of the soul be evil, - if the judgment be bribed and biassed by the corrupt and vicious dispositions of the mind, by pride and envy, by the love of the world and sensual pleasures, - if the understanding be prejudiced against divine truths, and resolved not to admit them, though brought with ever so convincing an evidence, - it is no wonder that the whole body, the whole soul, should be full of darkness, Luk 11:34. How can they have instruction, information, direction, or comfort, from the gospel, that wilfully shut their eyes against it? and what hope is there of such? what remedy for them? The inference hence therefore is, Take heed that the light which is in thee be not darkness, Luk 11:35. Take heed that the eye of the mind be not blinded by partiality, and prejudice, and sinful aims. Be sincere in your enquiries after truth, and ready to receive it in the light, and love, and power of it; and not as the men of this generation to whom Christ preached, who never sincerely desired to know God's will, nor designed to do it, and therefore no wonder that they walked on in darkness, wandered endlessly, and perished eternally.

No man, when he hath lighted, etc. - See on Mat 5:15 (note). Our Lord intimates, that if he worked a miracle among such an obstinate people, who were determined to disbelieve every evidence of his Messiahship, he should act as a man who lighted a candle and then covered it with a bushel, which must prevent the accomplishment of the end for which it was lighted. See also on Mar 4:21 (note), etc.

Take heed therefore,.... By attending to the light of the Gospel, shining in the ministration of it, and do not neglect and despise it:

that the light which is in thee be not darkness; lest being given up to a judicial blindness and hardness of heart, not only the light of nature, which the Jews had in common with the Gentiles, but even that notional light and knowledge of divine things, which they had by being favoured with an external revelation, the writings of the Old Testament, should be lost.

(See on Mat 5:14-16; Mat 6:22-23.) But Luk 11:36 here is peculiarly vivid, expressing what pure, beautiful, broad perceptions the clarity of the inward eye imparts.