The LORD who revealed Himself as YHVH in the Old Testament is revealed as Yeshua (Jesus) in the New Testament. Jesus shares the same attributes as YHVH and clearly claims to be YHVH. In John 8:56-59, Jesus presents himself as the "I AM." When challenged by some Jewish leaders regarding His claim of seeing Abraham (who lived some 2000 years earlier), Jesus replied, "Truly, truly, I say to you, before Abraham was born, I AM." Those Jewish leaders understood that Jesus was claiming to be YHVH. This is clearly established when they tried to stone Him to death for what they considered blasphemy under Jewish Law.
In Romans 10:9, Paul declares, "if you confess with your mouth Yeshua as LORD... you shall be saved." Immediately thereafter, in Romans 10:13, Paul backs up this declaration by quoting the Old Testament, "Whoever will call upon the name of the LORD (YHVH) will be saved" (Joel 2:32). Calling on Yeshua (Jesus) as Lord is the same as calling Him YHVH, because Yeshua (Jesus) is YHVH (LORD), the foretold throughout the entire Old Testament.
"YHVH" is the Hebrew word that translates as "LORD". Found more often in the Old Testament than any other name for God (approximately 7,000 times), the title is also referred to as the "Tetragrammaton," meaning the "The Four Letters". YHVH comes from the Hebrew verb "to be" and is the special name that God revealed to Moses at the burning bush. "And God said to Moses, 'I AM WHO I AM; and He said, thus you shall say to the sons of Israel, I AM has sent me to you... this is My eternal name, and this is how I am to be recalled for all generations'" (Ex. 3:14-15). Therefore, YHVH declares God's absolute being - the source of everything, without beginning and without end.
Although some pronounce YHVH as "Jehovah" or "Yaweh," scholars really don't know the proper pronunciation. The Jews stopped pronouncing this name by about 200 A.D., out of fear of breaking the commandment "You shall not take the name of YHVH your God in vain" (Ex. 20:7). (Today's rabbis typically use "Adonai" in place of YHVH.) Here are some examples of YHVH used in scripture: YHVH Elohim - LORD God: (Gen. 2:4). YHVH M'kadesh - The LORD Who Makes Holy: (Ezek. 37:28). YHVH Yireh - The LORD Who Sees/provides: (Gen. 22:14). YHVH Nissi - The LORD My Banner: (Ex. 17:15). YHVH Shalom - The LORD Of Peace: (Jud. 6:24). YHVH Tzidkaynu - The LORD Our Righteousness: (Jeremiah 33:16). YHVH O'saynu - The LORD our Maker: (Ps. 95:6).
All Bible references are from the Hebrew Names Version.