Easy answer.. context and spirit.. Mouthing the name of the lord is NOT calling on the name of the lord.. You can actually call out to God and not even use his name.. Its a spiritual thing.. In the spirit/Spirit, language is Not really needed.. deep can call out to deep..
As any that know the Lord but are deaf and/or dumb knows intimately..
I don't see any 'mouthing' in what these verses say: they say the same thing, but with opposite ending.
"Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven" (Mat 7:21-23)
"Whosoever shall call on the name of the Lord shall be saved." (Acts 2:21, Rom 10:13) and "Whosoever shall call on the name of the Lord shall be delivered." (Joel 2:32)
In the spirit/Spirit, language is Not really needed.. deep can call out to deep
Yup, you're right, it's deep alright.