Romans 15:4

For whatsoever things were written aforetime
In the books of the Old Testament; the apostle says this, to vindicate the pertinency of the above citation, and to prevent any objection that might be made against it; since whatsoever was written in that psalm did not belong personally to David, but to Christ; and what is written concerning him, is designed for the use and instruction of his people; yea, whatever is written anywhere in the sacred Scriptures,

were written for our learning;
to instruct in the knowledge of Christ, of his person, offices, grace, righteousness, obedience, sufferings, death, resurrection, and ascension; and of the great salvation and redemption he came to obtain, and has obtained; and to teach us the doctrines of grace, of pardon through the blood of Christ, atonement by his sacrifice, justification by his righteousness, acceptance in his person, and eternal life through him; as also to inform us of our duty, and how we ought to behave both towards God and men:

that we, through patience and comfort of the Scriptures, might have
hope;
the Scriptures are not only written for our present instruction, but for the ingenerating, encouraging, and establishing, an hope of eternal Life in another world; which they are the means of, under the influence of divine grace; since they give us a clear account of eternal life; of the promise of it in Christ; of its being procured by him, and secured in him; of the means of enjoying it, through his blood and righteousness; of the declarations of God's free grace and mercy to sinners, and of the various instances of persons who have been made partakers of it; all which encourage to hope in the Lord, and to rejoice in hope of the glory of God; believing we also may have and enjoy the thing hoped for, "through patience and comfort of the Scriptures"; both which are encouraged thereby: the "patience of the Scriptures" is not a stoical apathy, a stupid indolence; and is of a different kind from that patience the writings of the Heathen philosophers define and recommend: the Scripture gives an account of the true nature of patience, in bearing all sorts of evils for Christ's sake; of the excellency and usefulness of it; and do strongly exhort unto it upon the best principles, and with the best motives; and are full of promises to the exercise of it, and furnish out the best examples of suffering affliction, and patience: "the comfort of the Scriptures" is such as is not to be met with elsewhere. These writings abound with exceeding great and precious promises, and excellent doctrines, big with consolation to the saints; and both serve much to cherish, support, and maintain an hope of eternal happiness; all which prove the divine authority, excellency, and usefulness of the sacred writings, and recommend the reading of them by us, and the hearing of them explained by others.