A) A primary purpose of infant baptism is that it results in having the infant being 'sealed' (marked) by the Holy Spirit. The infant (obviously) has no ability to discern what is going on, so the faith is 'borrowed' from the godparents (who are then called upon to help raise the child in the faith). Frankly, I can't see any downside with any of that. The practice started in the first century, when infant mortality was a much bigger problem, and while there was a singular, universal church. Therefore, it is completely impossible to claim it is a 'Catholic invention'. The separate sacrament of Confirmation is what happens when a child is old enough to think for themselves (attains the 'age of reason') and therefore makes a profession of faith. Both practices were in place during the first century AD.

B) No Catholic 'grieves the Holy Spirit' by (properly) praying to Mary. A Catholic prays to Mary to ask her to intercede for them with her Son, and not with any expectation that she can perform whatever 'miracle' we might be asking for. She is not God. If you read the Old Testament, you can see how the kings held their mothers in high regard, with the 'Queen Mother' being someone who regularly interceded 'for the common man'. The king, having (sometimes) hundreds of wives, would not be swayed by the appeal of a wife, but did keep a special place (and royal chair) available for their mother. The term is Gebirah. A king would not refuse a request made by their mother on behalf of a subject (see 1 Kings 2:20).

So, lets say I was 'going in for surgery'... I would (obviously) pray directly to God, but I might also ask a family member, or friend, or neighbor to pray for me. (With no expectation that my family member, or friend, or neighbor could affect the outcome... I'm asking them to pray to God on my behalf.) This is called 'intercessory prayer'. Mary is no different. I pray directly to God, but I might also ask for her to intercede on my behalf. And 1 Kings 2:20 indicates that she 'has the king's ear' a bit more than my next-door neighbor.

C) Works are required. But not to 'earn your way into heaven'. Works are an essential part of faith itself. Consider this analogy... A father raises a child, and over the course of several years, the father imparts many 'words of wisdom' about 'how to live the best life possible' (how to be kind, loving, successful, responsible, etc). At some point, the child grows up and moves out. The question of 'whether the child believes the father' is determined by whether the child lives that way when they are on their own. If they do live that way, the child believes the father. If they do not live that way, then the father did not convince them of the best way to live (because they are living a different way). The child, therefore, does not have faith in what the father said.

Salvation is a free gift from God. We cannot earn it. But look at John 3:16. He who believes in the Son shall have eternal life. Alternatively, he who has been persuaded by the Son shall have eternal life. Been persuaded 'of what'? Of many things, including things like the Sermon on the Mount, where the Son describes the best way for us to live. But do we believe him? That can only be answered by how we live.

If you think that 'what we do' is not important, I'd guide you toward John 3:36. Just a few verses after John 3:16, the Bible makes perfectly clear that "he who believes shall have eternal life, and he who does not obey the Son shall not see life, but the wrath of God shall remain upon him." Works are an integral part of what it means to believe, what it means to 'have been persuaded'. John 3:36 (and other passages such as James 3:20-26) are very clear.

How in the world can you ignore Jesus' own warning in Matthew 25:41-46? How can you possibly say works are not integral to belief? Only those who believe the Son are saved.

If you don't agree, that's between you and God. I wish you well. Personally, I have been persuaded (by the Son) of the best way to live, and I do my (imperfect) best to live it out. I see no downside to it. It is exactly what I have been told to do by God.

Just to be clear, I addressed (at length) your statement regarding the Eucharist - complete with citations, explanations of typology, and commentary about the makeup of the 'crowd' in John 6.

A) Infant baptism does not result in 'salvation' (or even justification). It results in having the infant sealed (marked) by the Holy Spirit. The infant (obviously) has no ability to discern what is going on, so the faith is 'borrowed' from the godparents (who are then called upon to help raise the child in the faith). Frankly, I can't see any downside with any of that. The practice started in the first century, when infant mortality was a much bigger problem, and while there was a singular, universal church. Therefore, it is completely impossible to claim it is a 'Catholic invention'. The separate sacrament of Confirmation is what happens when a child is old enough to think for themselves (attains the 'age of reason') and therefore makes a profession of faith. Both practices were in place during the first century AD.

B) No Catholic 'grieves the Holy Spirit' by (properly) praying to Mary. A Catholic prays to Mary to ask her to intercede for them with her Son, and not with any expectation that she can perform whatever 'miracle' we might be asking for. She is not God. If you read the Old Testament, you can see how the kings held their mothers in high regard, with the 'Queen Mother' being someone who regularly interceded 'for the common man'. The king, having (sometimes) hundreds of wives, would not be swayed by the appeal of a wife, but did keep a special place (and royal chair) available for their mother. The term is Gebirah. A king would not refuse a request made by their mother on behalf of a subject (see 1 Kings 2:20).

So, lets say I was 'going in for surgery'... I would (obviously) pray directly to God, but I might also ask a family member, or friend, or neighbor to pray for me. (With no expectation that my family member, or friend, or neighbor could affect the outcome... I'm asking them to pray to God on my behalf.) This is called 'intercessory prayer'. Mary is no different. I pray directly to God, but I might also ask for her to intercede on my behalf. And 1 Kings 2:20 indicates that she 'has the king's ear' a bit more than my next-door neighbor.

C) Works are required. But not to 'earn your way into heaven'. Works are an essential part of faith itself. Consider this analogy... A father raises a child, and over the course of several years, the father imparts many 'words of wisdom' about 'how to live the best life possible' (how to be kind, loving, successful, responsible, etc). At some point, the child grows up and moves out. The question of 'whether the child believes the father' is determined by whether the child lives that way when they are on their own. If they do live that way, the child believes the father. If they do not live that way, then the father did not convince them of the best way to live (because they are living a different way). The child, therefore, does not have faith in what the father said.

Salvation is a free gift from God. We cannot earn it. But look at John 3:16. He who believes in the Son shall have eternal life. Alternatively, he who has been persuaded by the Son shall have eternal life. Been persuaded 'of what'? Of many things, including things like the Sermon on the Mount, where the Son describes the best way for us to live. But do we believe him? That can only be answered by how we live.

If you think that 'what we do' is not important, I'd guide you toward John 3:36. Just a few verses after John 3:16, the Bible makes perfectly clear that "he who believes shall have eternal life, and he who does not obey the Son shall not see life, but the wrath of God shall remain upon him." Works are an integral part of what it means to believe, what it means to 'have been persuaded'. John 3:36 (and other passages such as James 3:20-26) are very clear.

How in the world can you ignore Jesus' own warning in Matthew 25:41-46? How can you possibly say works are not integral to belief? Only those who believe the Son are saved.

If you don't agree, that's between you and God. I wish you well. Personally, I have been persuaded (by the Son) of the best way to live, and I do my (imperfect) best to live it out. I see no downside to it. It is exactly what I have been told to do by God.