Why not? Because they did not pursue it on the basis of faith, but as if it were based on achievements. They stumbled over the stone that causes people to stumble.

As it is written:Look! I am putting a stone in Zion to stumble overand a rock to trip over,yet the one who believes on Himwill not be put to shame.

I say, then, Did they stumble that they might fall? let it not be! but by their fall the salvation is to the nations, to arouse them to jealousy;

Do not destroy God's action for the sake of food. Everything is clean, but it is wrong to make another person stumble because of what you eat.

It is a noble thing not to eat meat, or drink wine, or do anything that makes your brother stumble.