Verse 11:[1] Behold, (Phil. 4:5; Rev. 1:3; 22:7, 12, 20) I come quickly: (Rev. 3:3; 2:25) hold that fast which thou hast, that no man take (Rev. 2:10) thy crown.
[Behold, I come (that is, I will come [Piscator]) quickly[2]] Either, 1. to send in that persecution against the Churches (Grotius); or, 2. to punish the guilty (Gomar), to destroy enemies (Pareus); or, 3. as about to help thee (Menochius, Tirinus, Lapide, thus Gagnæus), as about to carry thee away from the threatening danger (Tirinus), as about to crown thee (Menochius, thus Hammond); or, 4. for the final judgment (certain interpreters in Pareus, similarly Durham). He says quickly, 1. in comparison with eternity: 2. because this advent will be unexpected by enemies, and timely for His friends: 3. because He now makes haste concerning those things which precede His advent, etc. (Durham).
Behold, I come quickly; ταχύ, which certainly is the same with ἐν τάχει; and it might be as well concluded, that the day of judgment should come by that time Rome pagan should cease, as that all things written in this book had their accomplishment in that time, because Christ told John they should come to pass ἐν τάχει, Revelation 1:1;[3] 22:6.[4] No other coming of Christ, but his coming to the last judgment, can be here meant.

[Hold (that is, bravely preserve the thing apprehended [Ribera, similarly Menochius], hold fast constantly [Tirinus, Lapide]) what thou hast] That is, doctrine (Piscator), faith and a good conscience, according to 1 Timothy 1:19 (Pareus, similarly Cluverus), thy fortitude and patience (Ribera, Menochius, thus Lapide); proceed as thou didst begin, and yield to no terrors of persecutions (Ribera, Menochius). Hold fast thy faith and profession. I will preserve thee in life: See thou that thou failest not on account of fear. No one has accomplished so much that he ought not to watch himself, 1 Corinthians 9:27 (Grotius).
Hold that fast which thou hast; κράτει, hold with a strong hand the doctrine of faith, which thou yet hast, pure, and thy pure worship, and discipline, and a pure conscience.

[That no one take (that is, seize or carry off [Tirinus, thus Menochius, Ribera], snatch away or misappropriate [Piscator]) thy crown] Not that he might have it, but so that thou mightest not, or so that thou mightest lose it, as in Proverbs 5:9, Lest he give his honor to stangers, not which the strangers were going to have, but which by, and because of, them the young man was going to lose (Estius). Thy crown, that is, which was determined for thee (Piscator), and for the obtaining of which it is necessary that thou legitimately strive and overcome (Piscator, similarly Durham, Pareus). Lest another be substituted in thy place, another that would withdraw the crown that I had prepared for thee (Menochius). Lest thou lose the honor of perseverance, with others taking it. The loss of dignity burns more vehemently, if we are not only deprived of it, but we see that another gains possession of it, Job 34:24; Matthew 25:28 (Grotius). When one falls, God erects another in his place (Ribera, Pererius). But daily experience teaches that this is not perpetual (Tirinus). It is a metaphor from ancient contests (Gomar, similarly Durham), in which, someone running well in the beginning, another gets ahead and seizes first the palm (Durham). He exhorts, therefore, to constancy and perseverance (Pererius), for even those that are of advanced strength and near to the palm are yet able to be deprived of it (Ribera, similarly Lapide, Menochius, Lapide), if they should relax and not make provision. Hence those admonitions, Romans 11:20; 1 Corinthians 10:12 (Pareus).
That no man take thy crown; that thou mayest not lose that reward which shall be the portion of those that persevere to the end, and of those only.
[1] Greek: ἰδού, ἔρχομαι ταχύ· κράτει ὃ ἔχεις, ἵνα μηδεὶς λάβῃ τὸν στέφανόν σου. [2] Greek: ἰδού, ἔρχομαι ταχύ. [3] Revelation 1:1a: “The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly (ἐν τάχει) come to pass…” [4] Revelation 22:6: “And he said unto me, These sayings are faithful and true: and the Lord God of the holy prophets sent his angel to shew unto his servants the things which must shortly (ἐν τάχει) be done.”
Thomas Boston's Doctrines of the Christian Religion: 'The gospel is received in vain...When they are ashamed to appear for it, and have not a brow to keep and hold fast what the Lord has given. In vain is it received, that people have no confidence to hold fast when they have it, Revelation 3:11. How many are ashamed of gospel truths and ways! they will be gibed out of them. We must contend for the faith; and this is a day wherein the Lord seems to be calling this church to contend for those privileges which he has given her, and none have power to take from her, particularly that of appointing fasts and thanksgivings; though we should manage ou…
William Tong (for Matthew Henry): 'Christ calls the church to that duty which he before promised he would enable her to do, and that is, to persevere, to hold fast that which she had. (1.) The duty itself: "Hold fast that which thou hast, that faith, that truth, that strength of grace, that zeal, that love to the brethren; thou hast been possessed of this excellent treasure, hold it fast." (2.) The motives, taken from the speedy appearance of Christ: "Behold, I come quickly. See, I am just a coming to relieve them under the trial, to reward their fidelity, and to punish those who fall away; they shall lose that crown which they once seemed to have a righ…
Dr. Dilday's Sermon: "The Love of His Appearing"
https://www.sermonaudio.com/sermoninfo.asp?SID=116101811444
1) Introduction
2) Analysis
a) Context
b) Verse 11
i) “Behold, I come quickly”
ii) “Hold that fast which thou hast”
iii) “That no man take thy crown”
3) Use: Improve the typical comings of the Lord Jesus Christ by using them as instruction concerning the antitypical coming.
Hasten the Revelation series along: www.fromreformationtoreformation.com/super-summer-fund-raiser .