Exodus 6:5

⁵ And moreover I have heard the groaning of the children of Israel, whom the Egyptians keep in bondage; and I have remembered my covenant.

Lip

'A lip' in general signifies doctrine.

In Isaiah 6:3, 7, this signifies the interior parts of a person and thus internal worship where adoration is grounded.

In Isaiah 37:29, this signifies the thought of the understanding

In Malachi 2:6, 7, this denotes doctrine grounded in charity.