Revelation 3:3

Remember therefore how thou hast received and heard, and hold fast, and repent. If therefore thou shalt not watch, I will come on thee as a thief, and thou shalt not know what hour I will come upon thee.

Remember, therefore, how thou hast received and heard,.... That is, hast received upon hearing; for hearing goes first, and then receiving: the design of the advice is to put this church in mind of the doctrines of grace she had heard at the beginning of the Reformation, from Luther and others; such as justification by the righteousness of Christ, pardon through his blood, and atonement by his sacrifice, doctrines now almost lost and buried in forgetfulness; wherefore Christ would have her remember these things; how that she heard them with attention, reverence, humility, and without prejudice; and with much affection, so as to approve and love them, believe them, feel the power of them, and taste the goodness in them; and how she received them with all meekness, readiness, and joy, when now they are greatly disliked and rejected by many; very few attend to the doctrines of the Reformation. This is exactly our case:

and hold fast; the above doctrines, though the majority is against them, and learned men despise them, and they are charged with enthusiasm and licentiousness. It looks as if there was danger, as there is, that they would be entirely wrested out of her hands:

and repent: of her deadness, coldness, and indifference to these truths; of her unwatchfulness over them, and imperfection in them; not carrying truth to its fulness and perfection, resting in her first light and knowledge, and even going back from that:

If therefore thou shalt not watch: and preserve truth, and hold fast the form of sound words, and keep to the order, as well as the faith of the Gospel, and constantly attend divine worship, and look for the coming and kingdom of Christ:

I will come on thee as a thief; in the night, and at unawares, unthought of, and unexpected; which must be understood of coming to her in a way of rebuke and chastisement, by bringing some affliction, or suffering some sore distress to fall upon her: the phrase, "on thee", is left out in the Alexandrian copy and in the Ethiopic version:

and thou shalt not know what hour I will come upon thee: which, though applicable to the spiritual coming of Christ in the next church state, and to his second coming in his kingdom and glory, which will be both sudden and unexpected, yet these will be to the joy and comfort of the church; whereas what is here spoken is by way of threatening, and must relate to some severe dispensation on her; and which we might now justly expect, were we not in the unwatchful, unthoughtful, and ignorant situation here described.