To lye to lie to lay

Is it to lye or to lie or to lay?

"to recline whilst not telling the truth in a prone position?"

The greatest lies 

lie, lye, lay, lay in not telling the truth

but failing to lay at all.

Am I to never lye again,

but would that be a lie?

And not to tell the truth,

also be a lye?

Or a lay?

I must ensure that I would never again 

lie,

swearing the truth; to,

living,

lying

longing,

laying,

lying,

or just - lay; lye; lay; lie...

...why is liing not a word?