In Lydia's conversion there are many points of interest. It was brought about by providential circumstances. She was a seller of purple goods, from the city of Thyratira, but at just the right time for hearing Paul we find her at Philippi; providence, which is the servant of grace, led her to the right spot. Again, grace was preparing her soul for the blessing—grace preparing for grace. She did not know the Savior, but as a Jewess she knew many truths that were excellent stepping-stones to a knowledge of Jesus. Her conversion took place in the use of the means. On the Sabbath she went to a place of prayer, and there prayer was answered. Never neglect the means of grace.
God may bless us when we are not in His house, but we have more reason to expect that He will when we are in fellowship with His people. Observe the words, "The Lord opened her heart." She did not open her own heart. Her prayers did not do it; Paul did not do it. The Lord Himself must open the heart to receive the things that make for our peace. He alone can put the key into the door and open it and gain entry for Himself. He is the heart's Master just as He is the heart's Maker.
The first outward evidence of the opened heart was obedience. As soon as Lydia had believed in Jesus, she was baptized. It is a sweet sign of a humble and broken heart when the child of God is willing to obey a command that is not essential to his salvation, that is not forced upon him by a selfish fear of condemnation, but is a simple act of obedience and of communion with his Master.
The next evidence was love, displaying itself in acts of grateful kindness to the apostles. Love for the saints has always been a mark of the true convert. Those who do nothing for Christ or His church provide no evidence of an "opened" heart. Lord, grant to us the blessing of opened hearts always!