Lit. 'invoking,' 'calling on,' but in English we must have a word after this, which mars the connexion here. The Authorized Version seems to separate God and the Lord Jesus. 'Calling on the Lord' would leave out God. The Spirit of God, I doubt not, has purposely left out both 'Lord' and 'God'. No one can be called upon really but God, so that the word has great force as used here. I have said 'praying' for want of a better word.