God wasn't surprised by Abraham's faithfulness; perhaps He wanted to teach Abraham something. Strengthen his faith.
God provides everything for us. You and I were born with nothing, we will die with nothing; everything is on "loan".
But there is a treasure I can have, that I can take with me into the next life. You. And everyonen else reading this, if I can. The brothers and sisters that we love, are family; and if we can be family forever, then what joy we will have when Jesus returns. Well, for those who belong to Him, He's already returned in our hearts; there will be no great change when He comes back to earth, for we are with Him NOW in spirit and in truth just as much as we will be then.