In Revelation 6:1, this signifies attention and perception. (Apocalypse Explained 354)

354. "Come and see," signifies attention and perception. This is evident from the signification of "coming" when anything is presented to be seen, as being to give attention; for in a spiritual sense, "to come" means to draw near with the sight, thus to give attention; all attention also is a presence of the sight in the object. It is evident also from the signification of "to see," as being perception, for "to see" in the Word signifies to understand (See above, n. 11, 260); here it signifies to perceive, because this was out of the inmost heaven, since what comes out of the inmost heaven is perceived, but what comes out of the middle heaven is understood, for the reason that the inmost heaven is in the good of love, but the middle heaven is in the truths therefrom, and all perception is from good, and all understanding is from truths. (On this see above, n. 307; what perception is, see in The Doctrine of the New Jerusalem 140.)