How do we know God's calling is effective?

Romans 8:30 states, 'Moreover whom he did predestinate, them he also called: and whom he called, them he also justified: and whom he justified, them he also glorified.' This verse affirms that those whom God calls are not only called, but they also respond in faith. The efficacy of God's call ensures that it accomplishes what He intends; it is not a general invitation, but a specific call to His chosen ones who are enabled to believe and be justified. This aligns with the concept of irresistible grace, which indicates that when God calls, His elect will inevitably respond.