"Behold, God is my salvation; I will trust, and not be afraid: for the Lord JEHOVAH is my strength and my song; He also is become my salvation" (Isaiah 12:2).
The English name, usually written Lord in the English Bibles, stems from the Hebrew word, Yahweh, the meaning of which cannot be fully put into words. Although scholars differ (some even claiming there is no real meaning to the word at all), the consensus is that it seems to be a compound of the three tenses of the Hebrew verb "to be," implying the ever living nature of God to which Christ was referring when He said, "I am Alpha and Omega, the beginning and the ending, saith the Lord, which is, and which was, and which is to come, the Almighty" (Revelation 1:8). Note also the similar implications in God's announcement of Himself to Moses: "And God said unto Moses, I AM THAT I AM" (Exodus 3:14).
On forty-nine special occasions (seven times seven) the name Jehovah is contracted to Jah. Many consider this to be an abbreviation of Jehovah, but no satisfactory explanation as to why it is so used has been offered. Perhaps a better suggestion is that this name is the present tense of the verb "to be," and therefore the name Jah emphasizes the present activity of the Lord. In nearly all occurrences, the passages are strengthened by noting the present work of God. The first usage of the term Jah is found in Miriam's Song upon deliverance from Pharaoh's army and the Red Sea. "The Lord [Jah] is my strength and song, and He is become my salvation" (Exodus 15:2).
On several occasions, such as in our text, we see that the two names are combined, celebrating both the present and future deliveries of "Jah Jehovah." "Trust ye in the Lord [Jehovah] for ever: for in the Lord [Jah] JEHOVAH is everlasting strength" (Isaiah 26:4). JDM