Acts 10:11

And saw heaven opened
Not literally, as at the baptism of Christ, and the stoning of Stephen; but in a visionary way, and which was an emblem of the opening and revealing the mystery of the calling of the Gentiles, which in other ages was not made known, as it now and afterwards was:

and a certain vessel descending unto him, as it had been a great
sheet:
which seems to represent the church of God, whose original is from heaven, and consists of persons born from above, who have their conversation in heaven, and were designed for it; and especially as under the Gospel dispensation, which Peter had a vision of in this emblematic way; the doctrines and ordinances of which are from heaven: and which may be compared to a linen sheet for its purity and holiness; through the blood and righteousness of Christ, and the grace of his Spirit, and with respect to its discipline and conversation; and so to a great one for its largeness; for though the number of its members, when compared with the world, are few, yet in themselves are a number which no man can number; and though it was but small at first, yet the Gospel being carried among the Gentiles it increased, and in the last times will be large:

knit at the four corners;
which may denote the preaching of the Gospel, and the spread of it, and the planting of churches by it in the four parts of the world; and also the church being knit to Christ, and the members of it one to another:

and let down to the earth;
for Peter to see it, and where it was to continue for a while, even to the second coming of Christ, and when the whole church of the firstborn will be let down to earth again; see ( Revelation 21:2 ) .