Hebrews 5

8. Though He WAS (so it ought to be translated: a positive admitted fact: not a mere supposition as were would imply) God's divine Son (whence, even in His agony, He so lovingly and often cried, Father, Matthew 26:39 ), yet He learned His (so the Greek) obedience, not from His Sonship, but from His sufferings. As the Son, He was always obedient to the Father's will; but the special obedience needed to qualify Him as our High Priest, He learned experimentally in practical suffering. Compare Philippians 2:6-8 , "equal with God, but . . . took upon Him the form of a servant, and became obedient unto death," &c. He was obedient already before His passion, but He stooped to a still more humiliating and trying form of obedience then. The Greek adage is, "Pathemata mathemata," "sufferings, disciplinings." Praying and obeying, as in Christ's case, ought to go hand in hand.

9. made perfect--completed, brought to His goal of learning and suffering through death ( Hebrews 2:10 ) [ALFORD], namely, at His glorious resurrection and ascension.
author--Greek, "cause."
eternal salvation--obtained for us in the short "days of Jesus' flesh" ( Hebrews 5:7 ; compare Hebrews 5:6 , "for ever," Isaiah 45:17 ).
unto all . . . that obey him--As Christ obeyed the Father, so must we obey Him by faith.

10. Greek, rather, "Addressed by God (by the appellation) High Priest." Being formally recognized by God as High Priest at the time of His being "made perfect" ( Hebrews 5:9 ). He was High Priest already in the purpose of God before His passion; but after it, when perfected, He was formally addressed so.

11. Here he digresses to complain of the low spiritual attainments of the Palestinian Christians and to warn them of the danger of falling from light once enjoyed; at the same time encouraging them by God's faithfulness to persevere. At Hebrews 6:20 he resumes the comparison of Christ to Melchisedec.
hard to be uttered--rather as Greek, "hard of interpretation to speak." Hard for me to state intelligibly to you owing to your dulness about spiritual things. Hence, instead of saying many things, he writes in comparatively few words ( Hebrews 13:22 ). In the "we," Paul, as usual, includes Timothy with himself in addressing them.
ye are--Greek, "ye have become dull" (the Greek, by derivation, means hard to move): this implies that once, when first "enlightened," they were earnest and zealous, but had become dull. That the Hebrew believers AT JERUSALEM were dull in spiritual things, and legal in spirit, appears from Acts 21:20-24 , where James and the elders expressly say of the "thousands of Jews which believe," that "they are all zealous of the law"; this was at Paul's last visit to Jerusalem, after which this Epistle seems to have been written on "for the time").

12. for the time--considering the long time that you have been Christians. Therefore this Epistle was not one of those written early.
which be the first principles--Greek, "the rudiments of the beginning of." A Pauline phrase the first elements, but also "which they be." They are therefore enumerated Hebrews 6:1 Hebrews 6:2 [BENGEL]. ALFORD translates, "That someone teach you the rudiments"; but the position of the Greek, "tina," inclines me to take it interrogatively, "which," as English Version, Syriac, Vulgate, &c.
of the oracles of God--namely, of the Old Testament: instead of seeing Christ as the end of the Old Testament Scripture, they were relapsing towards Judaism, so as not only not to be capable of understanding the typical reference to Christ of such an Old Testament personage as Melchisedec, but even much more elementary references.
are become--through indolence.
milk . . . not . . . strong meat--"Milk" refers to such fundamental first principles as he enumerates in Hebrews 6:1 Hebrews 6:2 . The solid meat, or food, is not absolutely necessary for preserving life, but is so for acquiring greater strength. Especially in the case of the Hebrews, who were much given to allegorical interpretations of their law, which they so much venerated, the application of the Old Testament types, to Christ and His High Priesthood, was calculated much to strengthen them in the Christian faith [LIMBORCH].

13. useth--Greek, "partaketh," that is, taketh as his portion. Even strong men partake of milk, but do not make milk their chief, much less their sole, diet.
the word of righteousness--the Gospel wherein "the righteousness of God is revealed from faith to faith" ( Romans 1:17 ), and which is called "the ministration of righteousness" ( 2 Corinthians 3:9 ). This includes the doctrine of justification and sanctification: the first principles, as well as the perfection, of the doctrine of Christ: the nature of the offices and person of Christ as the true Melchisedec, that is, "King of righteousness" (compare Matthew 3:15 ).

14. strong meat--"solid food."
them . . . of full age--literally, "perfect": akin to "perfection" ( Hebrews 6:1 ).
by reason of use--Greek, "habit."
senses--organs of sense.
exercised--similarly connected with "righteousness" in Hebrews 12:11 .
to discern both good and evil--as a child no longer an infant ( Isaiah 7:16 ): so able to distinguish between sound and unsound doctrine. The mere child puts into its mouth things hurtful and things nutritious, without discrimination: but not so the adult. Paul again alludes to their tendency not to discriminate, but to be carried about by strange doctrines, in Hebrews 13:9 .