God did not pass by or skip over the houses with the blood, He actually leaped over the doors of those houses that had blood on them to protect all the first within from the destroyer, so that those who were within those bloodstained houses were protected under the shadow of God's wings.

By faith, Moses, when he had come to years, refused to be called the son of Pharaoh's daughter, choosing rather to suffer affliction with the people of God, than to enjoy the pleasures of sin for a season. For he esteemed the reproach of Christ greater riches than the riches of Egypt, for he had respect unto the recompense of the reward. By faith, he forsook Egypt, not fearing the wrath of the king, for he endured, as seeing Him who is invisible."