Cross reference
Exodus 6:30
30 And Moses saith before Jehovah, `Lo, I `am' of uncircumcised lips, and how doth Pharaoh hearken unto me?'
Exodus 6:12
12 and Moses speaketh before Jehovah, saying, `Lo, the sons of Israel have not hearkened unto me, and how doth Pharaoh hear me, and I of uncircumcised lips?'
Exodus 4:10
10 And Moses saith unto Jehovah, `O, my Lord, I `am' not a man of words, either yesterday, or before, or since Thy speaking unto Thy servant, for I `am' slow of mouth, and slow of tongue.'
1 Corinthians 9:16-17
16 for if I may proclaim good news, it is no glorying for me, for necessity is laid upon me, and wo is to me if I may not proclaim good news;
17 for if willing I do this, I have a reward; and if unwillingly -- with a stewardship I have been entrusted!