Shakespeare's Othello is a morality play in that its plot is similar to that of "The Garden of Eden" story in Genesis. The parallels between characters and setting are unmistakable. Desdemona, of course, plays the role of Eve; Othello is Adam; and Iago is the serpent, or devil. Cyprus, of course, is the Garden of Eden, where God (the laws of Venice) has left the couple open to temptation.
At the heart of both morality plays are trust and faith in a higher power (God, love) and the sins of the flesh (jealousy, lust). Iago plays the role of the devil, as he uses seductive words and symbols (the handkerchief) to outwit the unsuspecting. Unlike the Biblical parable in which the serpent seduced Eve first, Iago goes after the male Othello, whom he knows to be the jealous sort. Iago appeals to Othello's male pride and military honor culture, which permits little female freedom and unleashes swift punishment as consequence. In the end, the handkerchief becomes the forbidden fruit: he who possesses it must also possess Desdemona (flawed male logic). Jealousy is indeed the "green-eyed monster," turning the once-noble general Othello into a muttering, seizure-induced beast. Instead of feeling shame for their sins and accepting exile from the Garden, Othello mortally punishes the blameless Desdemona rather than live with the shame of being dishonored.
In Othello, their is little law to govern the morality, no God-figure to intervene. Cassio, Montano, and Lodovico cannot protect the women from the cruelties of men. Unlike the Fall of Man in Genesis in which Eve becomes a scapegoat, the tragedy in Othello rests firmly on the shoulders of men.