Now a certain woman named Lydia heard us. She was a seller of purple from the city of Thyatira, who worshiped God. The Lord opened her heart to heed the things spoken by Paul.
– Acts 16:14
We are saved by grace through faith, and though God extends his grace for all, it is up to us as individuals to open our hearts to the gospel. Think about an unbeliever you know, and pray specifically that God would open their heart so they can in turn believe, just as Lydia did.