Jamieson, Fausset and Brown on Song of Solomon 2:6

6. The "stay" she prayed for (So 2:5) is granted (De 33:12, 27; Psa 37:24; Is 41:16). None can pluck from that embrace (Joh 10:28-30). His hand keeps us from falling (Mt 14:30, 31); to it we may commit ourselves (Psa 31:5).

left hand--the left is the inferior hand, by which the Lord less signally manifests His love, than by the right; the secret hand of ordinary providence, as distinguished from that of manifested grace (the "right"). They really go together, though sometimes they seem divided; here both are felt at once. Theodoret takes the left hand, equivalent to judgment and wrath; the right, equivalent to honor and love. The hand of justice no longer is lifted to smite, but is under the head of the believer to support (Is 42:21); the hand of Jesus Christ pierced by justice for our sin supports us. The charge not to disturb the beloved occurs thrice: but the sentiment here, "His left hand," &c., nowhere else fully; which accords with the intensity of joy (So 2:5) found nowhere else; in So 8:3, it is only conditional, "should embrace," not "doth."