Confession is openly acknowledging Jesus Christ as Lord; calling on the Lord is turning to Him in faith for mercy and salvation.
These are not magic words or separate works added to faith, but the outward voice of a heart that has given itself to Christ. With the heart man believeth unto righteousness, and with the mouth confession is made unto salvation; and whosoever shall call upon the name of the Lord shall be saved.
To confess Jesus as Lord and to call on His name is simply faith speaking — owning the One to whom the believer already belongs.
See in Scripture: Romans 10:9–13; Joel 2:32; Acts 2:21; 1 Corinthians 12:3; Philippians 2:11