1) 6 If a man abide not in me, he is cast forth as a branch, and is withered; and men gather them, and cast them into the fire, and they are burned.
Here our holy Lord discovers the sad and deplorable condition of such professors, who, pretending relation to Christ, do yet bring forth no fruit unto him; he calls there withered branches, fit only for the fire. Learn hence, That such as have had a long standing in God’s vineyard, and contented themselves with a withered profession, are in great danger of having God’s blasting added to their barrenness. All their parts, and gifts, and common graces, will wither, and their fair blossoms of profession will drop off, and at the great day the angels will gather these fruitless branches together, and cast them into hell fire. William Burkitt, Expository Notes With Practical Observations on the New Testament (Philadelphia: Published by Thomas Wardle, 1835), 1:539-540; John 15:6. [Some spelling modernized, italics original, and underlining mine.]
2) Here the apostle advises the Corinthians, instead of inquiring after the proof of Christ in him, to examine whether they were in Christ themselves; intimating to us, that such are usually most backward to examine the state of their own souls, who are forward to inquire into the spiritual state and condition of others. “You seek a proof of Christ in me, says the apostle: O, rather prove and examine yourselves.” Where note, 1. A duty expressed: “Examine yourselves; prove yourselves.” The word is a metaphor taken from goldsmiths, who with great exactness try their gold; the truth of it by the touchstone, the weight of it by the scale, and the purity of it by the fire. And the repetition of the command, “Examine yourselves; prove yourselves;” implies the great backwardness that is in men’s natures to perform this duty, the great necessity of the duty, and the great diligence and frequency to be used in performing of the duty. Learn hence, that self-examination is an excellent, a necessary, and important duty, belonging to every one in the church, and requires great diligence and faithfulness in the performing of it. ‘Tis necessary in regard of our comforts, and also in regard of our graces; for there are counterfeit graces, as well as real; and common graces, as well as saving; and ’tis a duty that requires diligence and frequency, because the work is difficult, because the heart is backward, because we are deceived, and willing to be deceived; because many have miscarried without it, and many perished by a negligent performance of it: “Therefore examine yourselves; prove yourselves.”
William Burkitt, Expository Notes With Practical Observations on the New Testament (Philadelphia: Published by Thomas Wardle, 1835), 1:295; 2 Cor. 13:5. [Some spelling modernized, italics original, and underlining mine.]