Exodus 6:12 Moses spoke before Yahweh, saying, "Behold, the children of Israel haven't listened to me. How then shall Pharaoh listen to me, who am of uncircumcised lips?" (See NIV)
Exodus 6:30 Moses said before Yahweh, "Behold, I am of uncircumcised lips, and how shall Pharaoh listen to me?" (See NIV)
Job 4:4 Thy words have upholden him that was falling, and thou hast strengthened the feeble knees. (See NIV)