In colloquial language, it means that time is the most important consideration or factor.

RE:
What is the origin of "time is of the essence"?

Hi Carol, Hope you are doing great. I am happy to answer your distinctive question with my little knowledge and some acquired authentic information. Sorry for BIG Answer but highly worth reading fully. Amen is perhaps a word like no other, we most certainly use it hundreds of millions of times daily through out the planet earth to conclude prayer… with great declaration of Holy Affirmation. Yes, Etymologically the Word’s Root – Origin of “AMEN” is Purely Hebrew, widely believed with historical reference by linguistics account of Hebrew Bible. Amen is found in the Bible, of course, in Quaran. Beyond Judaism, Christianity and Islam, in the fading mists of early history, the word can be traced to ancient Egypt and a particular line of pharaohs, that of the Amun or Amen –hotep lineage. “ONE MUST UNDERSTAND THAT THERE ARE MANY SIMILAR WORDS WITH SIMILAR SOUNDS WITH IN THOUSANDS DIFFERENT LANGUAGES WITH NO QUESTION OF SIMILARITY IN MEANING OR RELEVANCY. THE WORD “AMEN” IS HOLY AND PURELY HEBREW, IT HAS IT’S OWN SACRED SENSE AND IT HAS NOTHING TO DO WITH EGYPTIAN PHARAOH NAMES”. – Hiram Raj Kamal Example: The Word ‘Aam’ or ‘Am’ – In Hindi it means Mango, In Japanese it means Supreme Truth, In English it is Am, In some other Indian Languages the meaning goes like Common, Layman, Jokes and Fun. I know too though some connect it with an Egyptian deity and the word has such an ancient etymology it is really impossible to say for sure. If it was originally Egyptian, they thought of the deity called by this name as hidden, mysterious, a deity powerful, yet one that worked behind the scenes. I could see, and this is conjecture now. How the Hebrews invading Egyptian culture could have taken this word and applied their own meaning to it, as their TRUTH, especially about God, was HIDDEN from the Egyptians. Then the Egyptians could have also have thought of the Hebrew God as Hidden, He being Invisible and so very different from their frogs and cats and rivers and gators and Pharaohs and all else called gods in Egypt. The source of this word I believe to be Hebrew (or pre-Hebrew; pre-Egyptian) maybe even part of Adam’s original language? Anyway, too early in its origin to be dogmatic. As a Christian, I can say Christ used it extensively and it has been brought to our culture through Christianity. Christ is the Amen. He used the word also prefacing His teaching with Amen, Amen for emphasis on it’s truth. AUTHENTIC REFERENCE: The word “Amen” makes its first appearance in the Bible under the most solemn circumstances. When a husband accused his wife of adultery, and she protested her innocence, and she had not been caught in the act, the matter was settled by God under the test of bitter water (Num 5:12-31). The woman was taken to the priest, and the priest put her under oath. She submitted to a ceremony in which she drank some water containing dust from the tabernacle floor. If she had committed adultery, she was be cursed with a wasting disease, but if she did not get sick, then she was proven innocent and her husband was proven wrong. During the ceremony, when the priest pronounced the curse, the woman was required by God to say, “Amen, Amen”. (Num 5:22). That is the first occurrence of the word in scripture. The LORD commands it to be said by a person who is yielding herself to examination by him in his presence. The word “Amen” probably goes back a long way. Some think it is of pagan origin (there was an Egyptian god called Amen-Ra). Perhaps that ancient usage reflects an even earlier existence of the word. As to its use in the Bible, however, we first encounter the word in this commandment spoken by the LORD (Num 5:22). The word is found in the last verses of the Bible (Rev 22:20-21). The first three books of Psalms end with Amen (Psa 41:13, Psa 72:19, Psa 89:52). Most books of the New Testament end with it (KJV). In the land of Israel, when a prayer or prophecy was made, or a law of God was read, “All the people said, “Amen”” (Neh 5:13, 8:6). The Lord’s example prayer ends with “Amen” (Mtt 6:13). Paul uses the word seven times in his letter to the Romans at the end of doxologies or benedictions (Rom 1:25, Rom 9:5, Rom 11:36, Rom 15:33, Rom 16:20,24,27) Paul implies that people should say “Amen” at the end of a prayer in church (1Co 14:16). The word “Amen” appears therefore to be the fitting last word for solemn utterances made before God. Amen.