@Fritzpw_Admin my brother.
I wholeheartedly agree that this proclamation by Jesus (Matt 12:36)“…that for every idle word men may speak, they will give account of it in the day of judgment.”, is indeed sobering, and one we all would be wise to live by. I appreciate the caution.
In the passage you are referencing, context is key to fuller understanding of what Jesus was speaking to; specifically, to whom He was speaking it. I know you know all this already, but for the edification of our readers…
According to the context Jesus was responding to the Pharisees who were acting in open opposition to his message. When they heard that the crowd had begun to ask “Could this be the son of David?” implying the long-awaited Messiah, the Pharisees countered the notion by saying, “This fellow does not cast out demons except by Beelzebub, the ruler of the demons.” Matthew 12:24. The members of this blasphemous opposition group are the direct recipients of the invective you mention.
It is in this same response Jesus tells the Pharisees
“Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men. Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come.” Matthew 12:31-22
And also:
“Brood of vipers! How can you, being evil, speak good things? For out of the abundance of the heart the mouth speaks.” Matthew 12:34
Jesus is not pointing a condemning finger at their “idle words” per se, but at the root of those words, their very heart, the source of their “idle” speaking:(“idle” specifically means, words that “do no work”, i.e. indolent, meaning “insincere”, “unprofitable”, “worthless”) . Jesus is not suggesting that the Pharisees be careful what they say, but that they examine the well from which their sayings are drawn. This is applicable advice for saint and sinner alike, but for different reasons:
“But I say to you that for every idle word men may speak, they will give account of it in the day of judgment. For by your words you will be justified, and by your words you will be condemned." Matthew 12:36-37
In other words, “Your heart will be revealed (exposed) by what comes out of your mouth. If not now, in the day of total revealing”.
In the meantime, my advice is:
“Do not be rash with your mouth, And let not your heart utter anything hastily before God. For God is in heaven, and you on earth; Therefore let your words be few. For a dream comes through much activity, And a fool’s voice is known by his many words.” Ecclesiastes 5:2-3
KP