Hebrews 12:15

“Looking diligently, etc..] Acting the part of bishops, or overseers, as the word signifies; and so this exhortation either respects officers of the church of the Hebrews, whose business it was more especially to inspect into the principles and practices of the members of it, and take care that they did not imbibe false doctrines, or live immoral lives; or rather the several members of the church, whose business it is to watch over one another, since this epistle seems to be written to the whole church. Lest any man fail of the grace of God; not the free favour and love of God in Christ, which is everlasting, unchangeable, and from whence there is no separation; nor the grace of God implanted…”

“lest any . . . fall--Greek, "lest any (namely, through sloth in running) failing," or "falling short of the grace of God . . . trouble you." The image is taken from a company of travellers, one of whom lags behind, and so never reaches the end of the long and laborious journey [CHRYSOSTOM]. root of bitterness--not merely a "bitter root," which might possibly bring forth sweet fruits; this, a root whose essence is "bitterness," never could. Paul here refers to Deu 29:18, "Lest there should be among you a root that beareth gall and wormwood" (compare Act 8:23). Root of bitterness comprehends every person (compare Heb 12:16) and every principle of doctrine or practice so radically corrupt as to…”

“Looking diligently - This phrase implies close attention. It is implied that there are reasons why we should take special care. Those reasons are found in the propensities of our hearts to evil; in the temptations of the world; in the allurements to apostasy presented by the great adversary of our souls. Lest any man fail - As every man is in danger, it is his personal duty to see to it that his salvation be secure. Fail of the grace of God - Margin, “fail from.” The Greek is, “lest any one be wanting or lacking” - ὑστερῶν husterōn. There is no intimation in the words used here that they already had grace and might fall away - whatever might he true about that - but that there was danger…”

“Looking diligently, lest any one - If he do not lift up the hands that hang down. Fall from the grace of God: lest any root of bitterness - Of envy, anger, suspicion. Springing up - Destroy the sweet peace; lest any, not following after holiness, fall into fornication or profaneness. In general, any corruption, either in doctrine or practice, is a root of bitterness, and may pollute many. Hebrews 12:16”

“12:15 The poisonous root of bitterness alludes to people turning their backs on God’s covenant to serve other gods (Deut 29:18). Bitterness can corrupt the church.”

“Looking: Heb 2:1, Heb 2:2, Heb 3:12, Heb 4:1, Heb 4:11, Heb 6:11, Heb 10:23-35; Deu 4:9; Pro 4:23; Co1 9:24-27; Co1 10:12; Co2 6:1, Co2 13:5; Pe2 1:10, Pe2 3:11, Pe2 3:14; Jo2 1:8; Jde 1:20, Jde 1:21 any man: Luk 22:32; Co1 13:8; Gal 5:4 fail of: or, fall from, Gal 5:4 any root: Heb 3:12; Deu 29:18, Deu 32:32; Isa 5:4, Isa 5:7; Jer 2:21; Mat 7:16-18 trouble: Jos 6:18, Jos 7:25, Jos 7:26, Jos 22:17-20; Eph 5:3; Col 3:5 and thereby: Exo 32:21; Kg1 14:16; Act 20:30, Act 20:31; Co1 5:6, Co1 15:33; Gal 2:13; Ti2 2:16, Ti2 2:17; Pe2 2:1, Pe2 2:2, Pe2 2:18 Hebrews 12:16”