From Great Difficulty Of Going To Heaven by John Bunyan,
1. Because the thing for which you are here exhorted to strive, is worth the striving for; it is for no less than for a whole heaven, and an eternity of felicity there. How will men that have before them a little honor, a little profit, a little pleasure, strive? I say again, how will they strive for this? Now, they do it for a corruptible crown, but we an incorruptible. Methinks this word heaven, and this eternal life, ought verily to make us strive, for what is there again either in heaven or earth like them to provoke a man to strive?
2. Strive, because otherwise the devil and hell will assuredly have thee:
“He goes about like a roaring lion, seeking whom he may devour,” 1 Peter 5:8.
These fallen angels, they are always watchful, diligent, unwearied; they are also mighty, subtile, and malicious, seeking nothing more than the damnation of thy soul. Oh, thou that art like the heartless dove, strive!
3. Strive, because every lust strives and wars against thy soul. The flesh lusteth against the spirit:
“Dearly beloved, I beseech you (said Peter), as strangers and pilgrims, abstain from fleshly lusts, which war against the soul,” Galatians 5:17.
It is a rare thing to see or find out a Christian that indeed can bridle his lusts; but no strange thing to see such professors that are not only bridled, but saddled too, yea, and ridden from lust to sin, from one vanity to another, by the very devil himself, and the corruptions of their hearts.
4. Strive, because thou hast a whole world against thee. The world hateth thee if thou be a Christian; the men of the world hate thee; the things of the world are snares for thee, even thy bed and table, thy wife and husband, yea, thy most lawful enjoyments, have that in them that will certainly sink thy soul to hell, if thou dost not strive against the snares that are in them, Romans 11:9.
The world will seek to keep thee out of heaven with mocks, flouts, taunts, threatenings, gaols, gibbets, halters, burnings, and a thousand deaths; therefore strive. Again, if it cannot overcome thee with these, it will flatter, promise, allure, entice, entreat, and use a thousand tricks on this hand to destroy thee; and observe, many that have been stout against the threats of the world, have yet been overcome with the bewitching flatteries of the same. There ever was enmity between the devil and the church, and betwixt his seed and her seed too; Michael and his angels, and the dragon and his angels, these make war continually, Genesis 3; Revelation 12. There hath been great desires and endeavors among men to reconcile these two in one, to wit, the seed of the serpent and the seed of the woman; but it could never yet be accomplished. The world says, they will never come over to us; and we again say, by God’s grace, we will never come over to them. But the business hath not ended in words; both they and we have also added our endeavors to make each other submit; but endeavors have proved ineffectual too. They, for their part, have devised all manner of cruel torments to make us submit; as, slaying with the sword, stoning, sawing asunder, flames, wild beasts, banishments, hunger, and a thousand miseries. We again, on the other side, have labored by prayers and tears, by patience and long-suffering, by gentleness and love, by sound doctrine, and faithful witness-bearing against their enormities, to bring them over to us; but yet the enmity remains: so that they must conquer us, or we must conquer them. One side must be overcome; but the weapons of our warfare are not carnal, but mighty through God.
5. Strive, because there is nothing of Christianity got by idleness:
“Idleness clothes a man with rags, and the vineyard of the slothful is grown over with nettles,” Proverbs 23:21; Proverbs 24:30-32.
Profession that is not attended with spiritual labor cannot bring the soul to heaven. The fathers before us were not slothful in business, but fervent in spirit, serving the Lord:
“Therefore be not slothful, but followers of them who through faith and patience inherit the promises,” Romans 12:11; Hebrews 6:12.
“Strive to enter in.” Methinks the words, at the first reading, do intimate to us, that the Christian, in all that ever he does in this world, should carefully heed and regard his soul, — I say, in all that ever he does. Many are for their souls by fits and starts; but a Christian indeed, in all his doing and designs which he contriveth and manageth in this world, should have a special eye to his own future and everlasting good; in all his labors he should strive to enter in:
“Wisdom (Christ) is the principal thing; therefore get wisdom, and in all thy gettings get understanding.” Proverbs 4:7.