Jamieson, Fausset and Brown on Song of Solomon 4:12

12. The Hebrew has no "is." Here she is distinct from the garden (So 5:1), yet identified with it (So 4:16) as being one with Him in His sufferings. Historically the Paradise, into which the soul of Jesus Christ entered at death; and the tomb of Joseph, in which His body was laid amid "myrrh," &c. (So 4:6), situated in a nicely kept garden (compare "gardener," Joh 20:15); "sealed" with a stone (Mt 27:66); in which it resembles "wells" in the East (Ge 29:3, 8). It was in a garden of light Adam fell; in a garden of darkness, Gethsemane, and chiefly that of the tomb, the second Adam retrieved us. Spiritually the garden is the gospel kingdom of heaven. Here all is ripe; previously (So 2:13) it was "the tender grape." The garden is His, though He calls the plants hers (So 4:13) by His gift (Is 61:3, end).

spring ... fountain--Jesus Christ (Joh 4:10) sealed, while He was in the sealed tomb: it poured forth its full tide on Pentecost (Joh 7:37-39). Still He is a sealed fountain until the Holy Ghost opens it to one (1Co 12:3). The Church also is "a garden enclosed" (Psa 4:3; Is 5:1, &c.). Contrast Psa 80:9-12. So "a spring" (Is 27:3; 58:11); "sealed" (Ep 4:30; 2Ti 2:19). As wives in the East are secluded from public gaze, so believers (Psa 83:3; Col 3:3). Contrast the open streams which "pass away" (Job 6:15-18; 2Pe 2:17).