How does Hale's speech express a message from the playwright?

The speech you are referring to occurs in act 4 once Hale's character has evolved to the point that he regrets his involvement in the witch hysteria that has stricken Salem. His speech reads as follows:

HALE: (To Elizabeth.) Let you not mistake your duty as I mistook my own. I came into this village like a bridegroom to his beloved, bearing gifts of high religion; the very crowns of holy law I brought, and what I touched with my bright confidence, it died; and where I turned the eye of my great faith, blood flowed upon it. Beware, Goody Proctor—cleave to no faith when faith brings blood. It is mistaken law that leads you to sacrifice. Life, woman, life is God‘s most precious gift; no principle however glorious may justify the taking of it. I beg you, woman—prevail upon your husband to confess. Let him give his lie. Quail not before God‘s judgment in this, for it may well be God damns a liar less than he that throws his life away for pride. Will you plead with him? I cannot think he will listen to another.

Hale explains to Elizabeth Proctor that he was wrong in his original intent. He has seen the trauma and suffering caused by the witch hunt, and he feels that he must help to put an end to it. He warns her against devoting herself to a faith that requires the believers to cause suffering to others. He does not think faith should result in bloodletting. Hale says that a true religion would not ask a believer to take the life of another. He urges Elizabeth to convince her husband John to confess (even though he'd be lying) to being a witch to save his life. John does not do so, thinking he cannot live with the sin of lying on his soul, and so he is put to death.
It is well-known that Arthur Miller wrote The Crucible during the McCarthy era in the 1950s to draw parallels between that era and the Salem witch trials. Here, the voice of the playwright can be heard warning the audience not to misplace their faith, out of fear, in a vengeful "witch hunt" that destroys lives and reputations. Like religion in the play, the government should not be trusted blindly; we should question its motives if it leads to citizens turning on one another, reveling in one another's suffering, or seeking to ruin or take away lives.