He's not yours; He's mine

As I sat at the edge of my seat in a cluttered bench of students, I listened to a short testimony of a student, Edsel, in form of a sermon. He talked about how he met this amazing girl and prayed to God if she could be his. But God simply told " she'll never be yours Edsel, because she'll always be mine." When I heard that, I was a bit confused. Wouldn't the person that you marry ultimately become yours? You are his and he is yours?
Then my dad told me about a man he knew that lost a wife and 2 children. He would cry daily and even took a year from work because he was that distressed. Then one night he had a dream where God asked him why he was crying, and told him that he mustn't cry because his children and wife were in His hands; they were never for the man, they were for Him.
We as humans, I believe, are possessive. We were born with it. If we bought it, earned it, has our name on it, it's ours.  If a toddler has a toy and another toddler tries to take it away, 9 out of 10 times, the first toddler will cry out "that's mine!". ( Unless, of course, the toddler loves to share). But we usually have some type of sense of possession, especially in relationships. So when I heard of the 2 accounts in which God told these two men that their potential girl/wife/children were not theirs, I was a bit confused. Yes I know everything that God has created is His. But didn't He make these things so that they may be ours?
In his sermon, Edsel went over the story of Hannah in 1 Samuel 1 and how she couldn't have a son. She prayed to God to have a son and told God that if she has a son then she will return the son back to Him. She would give her son to the Lord to further His work. And that was it. That was the answer to my confusion. God gives us these things that we posess so that we can bring people closer to Christ. Edsel used the example of tithes. When we work we receive a check and we take out tithes understaning the fact that what we have earned is not ours, it is for God. We are acting as stewards, in which we are just taking care of what is for our master. And this applies to everything else. Nothing that we believe to own is for us. Yes, God has given them to us, but He's the true owner. Now the quetion is: how are we utilizing them? Are we being selfish and use them for our own desires, or are we using it to tell others about Christ?