Mark seems to emphasis the gospel, in his text. Though Gill makes the inference both here and in Matthew 16:25. See text at end of post.

Mar 8:35 For whosoever will save his life shall lose it; but whosoever shall lose his life for my sake and the gospel's, the same shall save it.

Mat 16:25 For whosoever will save his life shall lose it: and whosoever will lose his life for my sake shall find it.

In the rest of Mark's text we see some keywords,

Mar 8:36 For what shall it profit a man, if he shall gain the whole world, and lose his own soul?

Mar 8:37 Or what shall a man give in exchange for his soul?

Mar 8:38 Whosoever therefore shall be ashamed of me and of my words in this adulterous and sinful generation; of him also shall the Son of man be ashamed, when he cometh in the glory of his Father with the holy angels.

Ashamed....

Paul proclaimed the gospel in 1 Corinthians 15 beginning with..

1Co 15:1 Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand;

Paul wrote...

Rom 1:16 For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek.

Rom 1:17 For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith.

Rom 9:33 As it is written, Behold, I lay in Sion a stumblingstone and rock of offence: and whosoever believeth on him shall not be ashamed.

2Ti 1:8 Be not thou therefore ashamed of the testimony of our Lord, nor of me his prisoner: but be thou partaker of the afflictions of the gospel according to the power of God;

2Ti 2:15 Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.

Soul....

Note earlier Jesus had taught.

Mat 10:28 And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell.

and lose his own soul? which is immortal and everlasting, when the world, and the glory of it pass away, and so is of more worth than the whole world. The world can only be enjoyed for a season, and that with a great deal of fatigue and trouble; but the soul continues for ever; and if it is lost and damned, its torment always abides, and the smoke of it ascends for ever, its worm never dies, and its fire is never quenched; See Gill on Mat 16:26. Gill

Matthew 16:26 (KJV)

26 For what is a man profited, if he shall gain the whole world, and lose his own soul? or what shall a man give in exchange for his soul?

Matthew 16:26 Gill

For what is a man profited,.... Such persons, though they are only seeking their own profit, will find themselves most sadly mistaken; for of what advantage will it be to such a man,

if he shall gain the whole world; all that is precious and valuable in it; all the power, pleasures, and riches of it; if with Alexander, he had the government of the whole world, and with Solomon, all the delights of it; and was possessed with the wealth of Croesus, and Crassus,

and lose his own soul? If that should be consigned to everlasting torment and misery, be banished the divine presence, and continually feel the gnawings of the worm of conscience that never dies, and the fierceness of the fire of God's wrath, that shall never be quenched, he will have a miserable bargain of it.

Or what shall a man give in exchange for his soul? Or, "for the redemption" of it, as the Ethiopic version renders it: see Psa 49:8. If he had the whole world to give, and would give it, it would not be a sufficient ransom for it; the redemption of an immortal soul requires a greater price than gold and silver, or any corruptible thing; nothing short of the blood and life of Christ, is a proper exchange, or ransom price for it. But in the other world there will be no redemption; the loss of a soul is irrecoverable: a soul once lost and damned, can never be retrieved. This passage is thought to be proverbial; what comes nearest to it, is the following (x).

"If a scholar dies, we never find an exchange for him; there are four things which are the ministry or service of the world, אם אבדו יש חליפין, if they are lost, they may be changed; and they are these, gold, silver, iron, and brass, Job 28:1 but if a scholar dies, לנו תמורתו מי מביא, who will bring us his exchange? or an exchange for him: we lost R. Simon, "who will bring us his exchange?".''

(x) Midrash Kohelet, fol. 72. 3, 4. T. Hieros. Beracot, fol. 5. 3.

Mark 8:35 Gill

For whosoever will save his life,.... Life is a valuable thing, and all that a man has he will give for it; self preservation is a principle in nature; and it becomes every man to take all lawful methods to save his life, when it is threatened, or is in danger: but whoever is willing to save it, when it is called for to be laid down for Christ's sake; and rather than lay it down, will deny Christ, and give up a profession of him, and his Gospel,
shall lose it: he shall not enjoy it with honour and comfort now, and much less with peace, pleasure, and happiness hereafter, but shall be under the power of the second death:
but whosoever shall lose his life for my sake and the Gospel's; that is, shall willingly part with it when he is called to it, rather than deny Christ and his Gospel,
the same shall save it: though he will lose it now, he will find it again in the resurrection of life; for he will rise to eternal life; when such, who have apostatized from Christ, will rise to shame, and everlasting contempt: this man will have greatly the advantage over such; they will die the second death, or be destroyed soul and body in hell; and he will live for ever with Christ, in endless pleasure and glory; See Gill on Mat 16:25.

Matthew 16:25 Gill

For whosoever will save his life,.... Whoever is desirous of preserving himself from troubles, reproaches, persecutions, and death; and takes such a method to do it, as by forsaking Christ, denying his Gospel, and dropping his profession of it; and by so doing, curries favour with men, in order to procure to himself worldly emoluments, honour, peace, pleasure, and life,

shall lose it; he will expose himself to the wrath of God, to everlasting punishment, the destruction of soul and body in hell, which is the second death, and will be his portion:

and whosoever will lose his life for my sake: that is, is willing to forego all the pleasures and comforts of life, and be subject to poverty and distress, and to lay down life itself, for the sake of Christ and the Gospel, rather than deny him, and part with truth,

shall find it; in the other world, to great advantage; he shall enjoy an immortal and eternal life, free from all uneasiness and affliction, and full of endless joys and pleasures.