24Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock:
25And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock.
26And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand:
27And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.
Rains. Floods. Winds. Jesus is saying that in a fallen world such disasters may befall the careful or the careless, the faithful or the faithless, but the foundation will determine whether the man has truly won or lost.
There is no guarantee in his insightful ethic (Sermon on the Mount) that the obedient one will be spared trials or tempests. But eternally the "wise man" is secure.
The term "acts of God" would appear to place all natural disasters within His volition. But then I am reminded of something which Paul said in Romans 8:
21Because the creature itself also shall be delivered from the bondage of corruption into the glorious liberty of the children of God.
22For we know that the whole creation groaneth and travaileth in pain together until now.
God wills it? God allows it? God trains through it in overcoming faith? God's goodness uses it to lead to repentance. Things get complicated.