Because I am so convicted in the beauty and power of this understanding of sex...
It is important to realize that as Christians, we believe that the pivotal moment of our salvation happened on the Cross. Everything in Catholic theology and teaching is somehow bound up in the Cross. "I desire to know nothing but Jesus Christ crucified" St. Paul preached. The Cross!
I would like to try to take a simple, Scriptural approach of WHY we as Catholics believe sex is such a sacred and holy thing, not to be thrown around, abused, or taken nonchalantly (and really, this teaching is meant for ALL people to accept and live out). I posted this in the past, but I am so convicted in the power of this teaching, that if people sincerely open their hearts to it, that it would gradually transform our culture and draw us out of the dumpster of immorality. I have no doubt! So I invite YOU to thoughtfully, sincerely, and open-heartedly consider the Catholic Church's understanding of sex.
Please follow my points, which I used to try to keep this as simple as possible:
1. Marriage is a sacrament that signifies that union of Christ with His Church. Christ is the bridegroom (husband) and the Church is the bride (wife). St. Paul in Ephesians 5:31-32 really cracks open this understanding for us. In this understanding, Christ has a spousal love for us; there is a nuptial relationship between Christ and His spouse, the Church.
2. We as Christians are called to love as Christ loves: “This is my commandment: love one another as I have loved you.” (John 15:12, John 13:34 to name a couple…but there are more references in Scripture that call us to imitate Christ).
3. Jesus Christ’s perfect act of love, that supreme gift of self which He gave himself over to us entirely, was on the Cross. “No one has greater love than this, to lay down one’s life for one’s friends.” (John 15:13). On the Cross is where we witness the totality of Christ’s spousal love for the Church – for us!
4. Within marriage, the most supreme gift of self and fullest and perfect expression of love that a husband and wife, can express is within the marital embrace, through sexual union.
...Thus from these conclusions, we can see a direct parallel between the Cross and sexual union within marriage. This is not to be confused with the idea that Christ’s love is sexual, but it must be understood that what makes sex reflective and parallel to the Cross is that sex is meant to be a supreme gift of self in a full and total way...
Back to my points…
5. On the Cross – that most perfect act of love – is Love itself, Jesus. “God is love.” (1 John 4:8 and 1 John 4:16). God is love, He pours forth love.
6. On the Cross, Jesus gave us life. It is by His death that we have life. This is the central and saving message of the Gospel! “He himself bore our sins in his body upon the cross, so that, free from sin, we might live for righteousness. By his wounds you have been healed.” (I Peter 2:24)
...So here, in that perfect act of love our Lord made on the Cross, we see Him pouring forth both His life AND His love to us. If we are so open, we receive life AND love. What takes place on the Cross is both a life-giving and love-giving gift of self.
Just so, in that perfect act of love that happens between a man and woman – sex – we should see a reflection and imitation of what Christ did for us on the Cross: life-giving and love-giving. What takes place in the sexual union should be both a life-giving and love-giving, gift of self. It should be an act that pours forth love AND is open to life (open to possibly conceiving the gift of a child as a result of that sexual act).
(Side note: ***By life-giving, I do not mean that every time a couple comes together in sex, they HAVE to conceive life, or HAVE to be willing to have a child. What is meant is that the couple bears in mind that by the very nature of the sexual act, it will always be a possibility that the spouses might conceive a child. They are open to the possibility of the gift of a new life, a child.***)
Therefore, anything that seeks to separate the love-giving aspect of sex from the life-giving aspect of sex is a counterfeit – a fake – of the sexual act as God intended it to be.
This is why it is such a mortal sin to do anything that separates these two aspects of sex: Because it does not reflect the most perfect love of Christ and it violates God's natural law. The specific things which are serious, mortal sins that jeopardize our souls and desecrate this sacred and intimate act include: Lust, fornication (sex outside of marriage), sexually impure acts even if not to the full degree of the sexual act, masturbation, in-vitro fertilization, sterilization, contraception and artificial birth control, surrogate motherhood, homosexual/LGBT acts, artificial insemination, breeding, and rape. My brothers and sisters in Christ, because I love you, committing these acts or assisting others in these things (even if you don't do them yourself) could bring your soul to hell if they are not repented of. These are grave matters.
Why? Why are these evil and grave acts of sin? Because each of these offends the dignity for which the sexual union was created; because each of these separates the life-giving aspect of sex from the love-giving aspect of sex. Jesus Christ did not “contracept” Himself on the Cross and hold Himself back from giving us life & His love. They are both given.
Remember, keep in mind...sex is reflective and parallel to the Cross in that sex is meant to be a supreme gift of self in a full and total way, just like Christ gave Himself in a complete and total way upon the Cross. (Read points #1-4 again, if needed)
Today, because of the influence of the culture we live in, many do not realize this. We get pounded and pounded with a message that is the exact opposite of this truth. It is no wonder that even many Christians and Catholics do not live according to God’s way in the realm of sexuality. For one thing, our culture gets pounded with a lie about sex from the father of lies. For another reason, many people have never heard this liberating and glorious message of what our Lord created sex to be (this was my own personal experience). In reality, what our society sells us is a cheap imitation of the real deal; it sells us a falsification of true love. Why do we settle for the dumpster when our Lord invites us to the banquet? So glorious is this truth of our sexuality!!
If men and women are to experience marriage, sex, as God intended it “in the beginning,” they must consciously renounce all that is contrary to God’s plan and continually surrender themselves to the grace of redemption. The cross of Christ, therefore, lies at the center of the Church’s theology of marriage.
This is what the Catholic Church teaches about sex. This is one simplified way that I tried to put this, although there is much to expound upon thanks to Pope Paul VI's "Humanae Vitae" and St. John Paul II's "Theology of the Body." But this is a rich and deeply beautiful truth! I cannot help to think that the reason people reject this reflection of God's love is because it is demanding. It is not easy. It is counter-cultural. It requires self-control; it requires self-sacrifice at times. It requires a deeper trust and surrender to God and His Divine Plan for our lives, not ours. It requires us to carry a cross. Let us beg God for these graces and a conversion of heart so that our love may be liberated from a the slavery to sin and a counterfeit, degrading version of love because His ways are truly amazing!
God has a plan for each and every family and so glorious is His work!