My sister, who I love dearly, is not a Christian. I started sending her information about Christianity and trying to chat to her about the Gospel, but in response she sent me information on human secularism, indicating this was her belief. How should I respond?
First, we commend you for your willingness to engage your family members in this important discussion. We know how challenging it can be to present the Gospel to family members, and we remember Jesus' words when He said:
Secular humanism is just the latest label for an age-old perspective that maintains human reason and wisdom are higher truths than religious faith. The information in your sister's response was simply copied from a well-known online resource for paganism and anti-religious viewpoints.
Even though she appears to be engaging with you in this debate, in reality your sister is attempting to shut down the conversation to prevent you from presenting the Gospel to her. She was probably hoping the material she copied and sent you would put an end to your efforts. Most likely your sister is uncomfortable in engaging in this discussion personally, perhaps out of ignorance or an insecurity, and so she relied on someone else's words instead.
Ironically, this may be a good thing for your purposes, since it suggests she may be unprepared to defend her views and that the Lord may be at work to open her eyes. Since your sister side-stepped the conversation, we recommend you keep trying to engage her in the very thing she is avoiding: the truth of God's word.
Rather than responding to her copied content point-for-point (which just moves you further away from the Gospel and God's word), continue to speak from Scripture. Explain the holiness of God and the sinful nature of men, explain the problem with our sin when it comes into the presence of a holy and just God Who must act in perfect justice, and explain the opportunity to escape that judgment by the grace of a loving God Who died for us. These are the facts your sister was probably trying to avoid as she threw up the smokescreen of describing secular humanism.
Finally, keep in mind that secular humanism is nothing new and nothing different. Since the time of Cain, men had tried to see themselves as independent of God and capable of finding truth apart from God. The reality of our accountability to an all-powerful, all-knowing God is both inconvenient and convicting, and so mankind has sought to suppress this conviction by changing the topic away from God and toward nature, science, fate, and other sources for human wisdom. Paul put it this way:
In reality, the enlightened reason of human secularism is neither enlightened nor reasonable. The Bible says the so-called wisdom of men is actually foolishness. The unbelieving men are deceived by the enemy, yet have no appreciation for the depths and power of that deception. Paul taught again:
Nevertheless, there is reason to hope that your efforts to reach your sister will be effect. God is capable of breaking through your sister's blindness and bringing her to a knowledge of the truth. Paul says it this way:
Paul taught that the story of the cross of Christ was designed by God to sound foolish to those who think themselves wise, so He may shame human wisdom by His plan of salvation. God also delights, however, to save those who believe in the message of the Gospel by the power of God. And the foolish and weak message of the Gospel is far wiser than the so-called wisdom of men, and the power of the Gospel to save is far stronger than the strength of men to save themselves by their efforts at "reason."
Therefore, take heart in knowing that if God is at work through you to save your sister, then His efforts cannot be stopped, and your sister's adherence to pagan principles will one day give way to the truth of the Gospel. In the meantime, continue to focus your conversation on the truth of the Gospel and don't get distracted in debates over things she copies from the internet and throws in your face. Like all unbelievers, she desperately needs to hear the very conversation she is trying to avoid.