4:10 my sister. Four times, he calls her “my sister, my spouse” (Song of Solomon 4:9; 4:12; 5:1), denoting holy fellowship as well as marital life. Similarly, Christ “is not ashamed to call [them] brethren” (Hebrews 2:11).
4:12 garden enclosed. The bride was a virgin, whose “garden of spices” was opened first and only to her beloved spouse.