John Calvin Commentary Acts 16:15

"And when she was baptized, and her household, she besought us, saying, If ye have judged me to be faithful to the Lord, come into my house, and abide [there]. And she constrained us." — Acts 16:15 (ASV)

When she was baptized. By this it appears how effectually God worked in Lydia even in a short time. For there is no doubt that she received and embraced the faith of Christ sincerely, and professed His name, before Paul would admit her to baptism. This was a token of sheer readiness; also, her holy zeal and godliness show themselves in this, because she also consecrates her family to God.

And surely, all the godly should have this desire: to have those under their care be sharers in the same faith. For he is unworthy to be numbered among the children of God, and to be a ruler over others, whoever desires to reign and rule in his own house over his wife, children, and servants, and does not give Christ His place.

Therefore, let every one of the faithful strive to govern and order his house so that it may be an image of the Church.

I grant that Lydia did not have control over the hearts of everyone in her household, so that she could turn to Christ whomever she wished; but the Lord blessed her godly desire, so that her household was obedient to her.

The godly, as we have already said, must endeavor with all their might to drive every form of superstition from their houses. Secondly, they must ensure they do not have profane families, but instead keep them under the fear of the Lord.

So Abraham, the father of the faithful, was commanded to circumcise all his servants with him; and he is commended for the care he took to govern his house and instruct his family.

Furthermore, if this duty is required of the head of a household, it is much more required of a prince, that he not allow, as much as is in his power, the name of God to be profaned in his realm.

She besought them, saying. This has the force of an adjuration, when she says, if you have judged me faithful. It is as if she were saying, 'I beseech you by that faith which you have approved by baptism, that you do not refuse to lodge with me.' Lydia, by such an earnest desire, testified how entirely she loved the gospel.

Nevertheless, there is no doubt that the Lord gave her such an affection so that Paul might be more encouraged to proceed. This was not only because he saw that he was generously and courteously entertained, but also because he could thereby judge the fruit of his doctrine.

Therefore, this was not only the woman's invitation, but also God's intention to keep Paul and his company there. To this end, it also contributes that Lydia constrained them, as if God laid His hand upon them and detained them through the woman.