"I am sending you out as sheep among the wolves. Therefore, be shrewd as snakes and innocent as doves." Matthew 10:16
I don't think of being 'shrewd as a snake' very often. Maybe ever. To me, the word shrewd makes me think of dirty public servants--cops, politicians--who use situations to their advantage, who deal under the table, accept bribes for favors. Cunning and tricky are the synonyms that come to mind. Clearly, though, this isn't what Jesus means by shrewd in this statement. He means for His disciples to be sharp of mind, to use the Word as Hebrew puts it, "Sharper than any two-edged sword, penetrating even to dividing soul and spirit, joints and marrow."
There's a good example of such gospel shrewdness in Acts 23, when Paul is arrested in Jerusalem, and the Jewish leaders plan to kill him. He asks/gets permission to speak, then looks out at the crowd and sees two distinct factions of Jews. Sadducees don't believe in the resurrection from the dead and Pharisees do. Paul, having been a pharisee, knows clearly just how deep and divisive these beliefs are, and speaks carefully, using shrewd, loaded language. "I stand on trial for the hope of the resurrection from the dead." He cuts to the heart of the matter for these two groups, and in naming their difference, causes a riotous debate between them. They are distracted from their earlier singular purpose of wanting Paul's death. Their unity is exposed as superficial, and Paul knew this would happen. Shrewd as a snake.
And so Jesus calls us to be. To look beneath the surface of situations, to have acute perception about the arguments, the complains, the brokeness of those around us, and see the world (and those who would come against us) for what they really are. Things are not always, or even usually, what they seem in this world. There is always sin and darkness and division lurking, trying to divide us from Him.
But He also calls us to be innocent as doves. To fly high above the fray as people in whom the Holy Spirit dwells. He calls us to where peace reigns--out of the orbit of sin and greed, and division from truth. He calls us NOT to be subject to that world, but to live as transformed, high-flying creatures of new life. "Don't let the world around you squeeze you into its mold," Romans 12:2 (in the Living Paraphrase) says, "but let God remold your minds from within. It's an enlightening way to look at transformation, this being remolded into something 'other'--something like an simple bird. Into His likeness.The innocence of doves and the shrewdness of snakes. Both at once.