And to make clear as I said earlier it has been noted that there are certain parallels between the rich man who comes before Jesus in chapter 10 and the rich youth in Secret Mark who follows. Both are rich, in the former Jesus loves the man, in the latter the youth loves Jesus. But the prediction at the end of the section can be seen as an allusion to the (brother-making) ritual follows in Secret Mark:
But Christ is the fulfilment of the law for righteousness to every one that believes; and not as a slave making slaves, but (as a son making) sons, and (a brother making) brethren, and (an heir making) fellow-heirs, who perform the Father's will (οὐχὶ δὲ δούλους ποιῶν ὡς δοῦλος, ἀλλὰ καὶ υἱοὺς καὶ ἀδελφοὺς καὶ συγκληρονό μους τοὺς ἐπιτελοῦντας τὸ θέλημα τοῦ πατρός).
which is generally argued to be a reference to the baptism reference in Romans
The Spirit you received does not make you slaves, so that you live in fear again; rather, the Spirit you received brought about your adoption to sonship. And by him we cry, “Abba, Father.” The Spirit himself testifies with our spirit that we are God’s children. Now if we are children, then we are heirs—heirs of God and co-heirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory.
Clement seems to blend Romans 8:14 - 17 with certain passages of the gospel where Jesus speaks of being a fellow-heir and a brother:
Romans 8.17 εἰ δὲ τέκνα, καὶ κληρονόμοι· κληρονόμοι μὲν θεοῦ, συγκληρονόμοι δὲ Χριστοῦ, εἴπερ συμπάσχομεν ἵνα καὶ συνδοξασθῶμεν.
• συγκληρονόμος (Protr. 113.5 [p. 80 l. 11]) [All]
• συγκληρονόμον (Protr. 115.4 [p. 81 l. 25]) [All]
• συμποτικὰς (Protr. 115.4 [p. 184 l. 10] BP1) [All]
• συγκληρονόμους (Strom. 2.134.2 [p. 187 l. 10] BP1) [All]
• + from 8.18 εἴπερ συμπάσχομεν, ἵνα καὶ συνδοξασθῶμεν, ὡς συγκληρονόμοι Χριστοῦ (Strom. 4.45.6 [p. 269 l. 3] BP1) [Ad]
• συγκληρονόμους υἱοὺς καὶ φίλους. ἀδελφοί μου γάρ, φησὶν ὁ κύριος, καὶ συγκληρονόμοι οἱ ποιοῦντες τὸ θέλημα τοῦ πατρός μου. (Ecl. 20.3 [p. 142 l. 13]) [All – Also C Mt. 12.50]
• οὐχὶ δὲ δούλους ποιῶν ὡς δοῦλος, ἀλλὰ καὶ υἱοὺς καὶ ἀδελφοὺς καὶ συγκληρονόμους τοὺς ἐπιτελοῦντας τὸ θέλημα τοῦ πατρός. (Quis div. 9.2 [p. 165 l. 22] BP1) [All – Also Mt. 12.50]
• τέκνον αὐτοῦ γνήσιον καὶ κληρονόμον (Quis div. 36.2 [p. 183 l. 25] BP1) [All – Also 1 Tim. 1.2; Tit. 1.4]
So in Ecologue 19 and 20:
XIX. Advancing from faith and fear to knowledge, man knows how to say Lord, Lord; but not as His slave, he has learned to say, Our Father. [4] Having set free the spirit of bondage, which produces fear, and advanced by love to adoption, he now reverences from love Him whom he feared before. For he no longer abstains from what he ought to abstain from out of fear, but out of love clings to the commandments. "The Spirit itself," it is said, "beareth witness when we cry, Abba, Father."
XX. Now the Lord with His precious blood redeems us, freeing us from our old bitter masters, that is, our sins, on account of which the spiritual powers of wickedness ruled over us. Accordingly He leads us into the liberty of the Father, -- sons that are co-heirs and friends. "For," says the Lord, "they that do the will of my Father are my brethren and fellow-heirs." [6] "Call no man, therefore, father to yourselves on earth." [7] For it is masters that are on earth. But in heaven is the Father, of whom is the whole family, both in heaven and on earth. [8] For love rules willing hearts, but fear the unwilling. One kind of fear is base; but the other, leading us as a pedagogue to good, brings us to Christ, and is saving.
It seems to suggest that baptism was not only a rite to establish the initiates as sons and fellow-heirs but also brothers of each other and Christ.
“Finally, from so little sleeping and so much reading, his brain dried up and he went completely out of his mind.”
― Miguel de Cervantes Saavedra, Don Quixote