Follow after love (διωκετε την αγαπην). As if a veritable chase. Paul comes back to the idea in 1. Corinthians 12:31 (same use of ζηλουτε) and proves the superiority of prophecy to the other spiritual gifts not counting faith, hope, love Rev 1. Corinthians 13:13.

But rather that ye may prophesy (μαλλον δε ινα προφητευητε). Distinct aim in view as in verse 1. Corinthians 14:5. Old verb from προφητης, common in N.T. Present subjunctive, "that ye may keep on prophesying."