Psalm 27

BibleGateway.com Psalm 27

The LORD is our light and salvation. How often do we think that this term "The LORD" just means a generic term for God? Kind of like calling God the King? When you see the term "The LORD" this is the name of God. Yahweh. You might know it as the mis-translation of Jehovah. The name of God is important. God told Moses what the he is "I AM". Which is the name of the LORD, or Yahweh translated. So when David writes here The LORD is my my light and my salvation he is pointing to a specific God. The same God that talked to Moses as the form of a burning bush. The same God that made a covenent with Abraham.
When Christians say that Jesus is Lord, they are connecting the dots of divinity from Abraham, Isaac, Jacob, Moses, David all the way to Jesus. The old testament points to Jesus at every turn it seems.
Some people may say, "Jesus never said he was Yahweh. He never claimed to be God." This is a lie. in John 8 Jesus says plainly, "I tell you the truth," Jesus answered, "before Abraham was born, I am!"
He didn't say I am older than Abraham. If he had said that, the people would have known he was a fraud. When Jesus says, "I am" he is saying I am the always existing LORD. The I AM. We know this is what he meant and this is what was understood by the people he talked to by their reaction.
Read John 8 and see for yourself. He tries to tell the people who is numerous times, he finally has to be blunt enough to tie who he is to the same phrase he used when he talked to Moses in the burning bush. They know exactly who Jesus is, and they want to kill him for it.