Help me understand here

Ahh. I have been debating whether I should bring this up or not. I have been irritated about something for a few days and I'd like to ask your input/opinion. If I come across sounding harsh, I apologize. I am just irked.

I think I've mentioned before that some of my family (who are not Lutheran but another Christian denomination) seem suspicious of us, as if we're not really Christians. Some wouldn't come to our wedding because it was in a Lutheran church.

There is one fellow in particular who is troubling me. He has been pestering my children about their baptisms, in particular my son Brent. It seems he thinks that their baptisms, because they were performed when they were infants, don't "count". For a while, he was pressing them to "make a decision" until I told him to lay off. (To my kids credit, they told him that they didn't need to make a decision, because Christ had already claimed them in their baptism. My kids were VERY well catechized.)

I have made my position very clear to him. I reject "decision theology" because carnal man, dead in his sins, is unable to choose that which is spiritually discerned. We have taught our children that baptism is not merely a symbolic ordinance, but a means of grace by which God creates saving faith and brings the one baptized into the family of God. It's not the only way that God creates faith and extends his grace, but Scripture insists that it is one of them. (Mark 16:16, Acts 22:16, 1 Peter 3:21, Titus 3:5 and on and on.) And I can find no Scriptural evidence that children are excluded from God's grace.

Lately he's been bugging them to come to their youth group even though my kids already attend their own. I don't object to them going to the youth group, but I suspect that this is a ploy to try and get them alone so he can bug them some more to "accept" Christ. And I'm afraid that the kids might, though they are already believers, go along with him just to end the pestering.

The reason that this is such a touchy issue for me is a bit of a long story, but I'll give you the abbreviated version here. Growing up, my husband, though he had "accepted" Christ as his Saviour (many times, in fact) lived in terror that he was not really saved. Why? Because he was told that "all he had to do" was have faith and he would be saved, but he could never be sure that he was truly saved under the strength of his own faith. It was not until several years into our marriage that the Spirit revealed the truth of Eph. 2:8-9 to him - that it wasn't his faith that saved him, it was God's grace through faith, and that faith itself was a gift from God.

My kids get this. They understand that God did it all. I do not want them robbed of this certainty, no matter how well-meaning my nephew is.

So, without this devolving into a theological war, I'd like to understand why he won't accept this? What can I say that will convince him (or at the very least get him to back off)? Sara, Beth, you've been on both sides of this. What do you think?

Also, just out of curiosity, any idea why they are so suspicious of us?