Poole on Revelation 3:8: An Open Door
Verse 8: (Rev. 3:1) I know thy works: behold, I have set before thee (1 Cor. 16:9; 2 Cor. 2:12) an open door, and no man can shut it: for thou hast a little strength, and hast kept my word, and hast not denied my name.
[I know thy works] That is, thy labor in propagating the Gospel (Grotius, similarly Ribera, Menochius).
[I have given (that is, I have set: for δοῦναι, to have given, and τίθεσθαι, to have set, mutually explain each other, as do נָתַן, to give, and שִׂים, to set [Drusius]) before thee (ἐνώπιόν σου, before thee, in the place of σοι, to thee, as also in Revelation 2:14 [Grotius]: I set before thee [Piscator]: I set in thy sight [Beza]) an open door] That is, a door of preaching and of the conversion of the nations (Menochius), an occasion and opportunity of freely proclaiming the Gospel (Grotius, similarly Piscator, Gomar), as in 1 Corinthians 16:9; 2 Corinthians 2:12; Colossians 4:3, in which places see what things are said. And this well agrees with what was said above, I opened, and who will shut? (Grotius), or, the extension of the Church (certain interpreters in Gomar), for, by thy preaching, many men will enter into the Church (Ribera, similarly Lapide), both Jews and Gentiles (Lapide), and neither the Devil nor his ministers shall prevail to impede their entrance: that is to say, Thou shalt be so far from losing of thine own that thou shalt gain to Christ many even from among the infidels (Ribera). Out of a comparison with what precedes, I understand by an open door a preservation in the Church and way of salvation, concerning which thing see John 10:28; 1 Peter 1:5, from which Satan and his ministers were desiring to exclude, urging to defection, partly by false doctrine and deceit, partly by force and persecution (Grotius). Others: He understands in this place, not so much liberty from external impediments, as internal liberty and παῤῥησίαν, freedom of utterance, given to the minister, by which he preaches with power and success, with God opening the ears and hearts of the people. That which is called a door of utterance, Colossians 4:3, is also said to be opened, even where there are many adversaries, 1 Corinthians 16:9. Hence it has happened that those that are furnished with lesser gifts often have greater success, etc. (Durham).
[No one is able to shut] That is, no one will be able to impede that liberty of preaching (Grotius).
I know thy works: it is very probable, that our Lord, by these ministers’ works, understands the works proper to them in their function, their labour in preaching and propagating the gospel, which Christ did not only know and observe, but also approve of, and promiseth them a liberty to go on, and success in their labours, under the notion of an open door: see 1 Corinthians 16:9; 2 Corinthians 2:12; Colossians 4:3. And no man can shut it; so as it should not be in the power of adversaries to hinder his success.
[For, etc., ὅτι μικρὰν ἔχεις δύναμιν] For moderate (or, some [Beza, Piscator], a little [Piscator]) strength thou hast (Erasmus, etc.), that is, either, 1. vigor of soul, or fortitude (Piscator), for resisting so many adversaries (Pareus, similarly Ribera). Or, 2. external strength, human reinforcement from powerful friends (Gomar, similarly Ribera, Pareus). Or, 3. health and strength of body (certain interpreters in Lapide). Or, 4. strength both natural and supernatural (Tirinus), which are needful for the conversion of infidels, especially the Jews (Lapide, similarly Tirinus): that is to say, Many talents gave I not to thee, namely, of miracles (Cluverus, thus Lapide), of knowledge and eloquence (Lapide, similarly Tirinus, Cluverus, Durham): therefore, thou art afraid and distressed. But be thou of good courage; what is wanting on thy part, I shall supply on my part (Tirinus), and I will cause it to be that thou shalt overcome and convert them (Lapide). God often makes use of feeble, unlearned, inarticulate men for the greatest things (Lapide, similarly Durham). [Others: The sense is:] I did this because now thou hast a modest Church, which is here called δύναμις/strength, that is, an army, צָבָא, as in Matthew 22:29, 30, following the example of Daniel, in whose book the Jewish people are called δύναμις τοῦ οὐρανοῦ, the power of heaven, Daniel 8:10 (Grotius). Others: The sense is that thou dost acknowledge thyself to be capable of little, to have little strength; for not in those things, but in God, dost thou place thy hope (Aquinas and Haymo and Primasius and Bede in Lapide). But here He does not at all intend the weakness of grace, for this is especially commended in him, etc. (Durham).
For thou hast a little strength; both inward strength, and outward helps and advantages.
[And thou hast kept my word] That is, Thou hast held fast the faith (Menochius), and hast preached, and shown in practice the faith (Durham). And thou hast yet persisted in observing my precepts. See Revelation 3:3 (Menochius).
And hast kept my word; the doctrine of faith is by thee kept pure, as also my precepts for a holy life.
[And thou hast not denied, etc.] But thou hast confessed (Menochius). Thou hast not concealed that thou art a Christian (Grotius).
And hast not denied my name; and thou hast not been by any temptation prevailed upon to apostatize from the profession of the gospel.
 Greek: Οἶδά σου τὰ ἔργα (ἰδού, δέδωκα ἐνώπιόν σου θύραν ἀνεῳγμένην, καὶ οὐδεὶς δύναται κλεῖσαι αὐτήν), ὅτι μικρὰν ἔχεις δύναμιν, καὶ ἐτήρησάς μου τὸν λόγον, καὶ οὐκ ἠρνήσω τὸ ὄνομά μου.  Revelation 3:8a: “I know thy works: behold, I have set (δέδωκα) before thee an open door, and no man can shut it…”  Ἐνώπιον/before can take either the Gentive (σου) or the Dative (σοι); the meaning is unaffected.  Revelation 2:14b: “…who taught Balac to cast a stumblingblock before the children (ἐνώπιον τῶν υἱῶν, taking the Genitive) of Israel…”  Matthew 22:29, 30: “Jesus answered and said unto them, Ye do err, not knowing the scriptures, nor the power (τὴν δύναμιν) of God. For in the resurrection they neither marry, nor are given in marriage, but are as the angels of God in heaven.”  Daniel 8:10: “And it waxed great, even to the host of heaven (צְבָ֣א הַשָּׁמָ֑יִם; τῆς δυνάμεως τοῦ οὐρανοῦ, the power/host of heaven, in Theodotion); and it cast down some of the host (הַצָּבָא; τῆς δυνάμεως τοῦ οὐρανοῦ, the power/host of heaven, in Theodotion) and of the stars to the ground, and stamped upon them.”