I know someone who takes this verse (Ro 10:9) as meaning that you need to believe in your heart and then pray in order to be saved. I'm thinking the "confess with your mouth" part of the verse is more in correlation to the principle behind Mt 10:32-33, i.e., confessing before men. Can one be saved who "believes" and "prays" but is not willing to confess Jesus before men? What about him who "believes" and "prays" but does not repent? I think the Bible says no.