'Hard' in the Bible

You whose hearts are hard and whose ears are shut to me; you are ever working against the Holy Spirit; as your fathers did, so do you.

Now Saul, still breathing threats and murder against the disciples of the Lord [and relentless in his search for believers], went to the high priest,

And he said, Who art thou, Lord? And the Lord said, I am Jesus whom thou persecutest: it is hard for thee to kick against the pricks.

But Saul, whose other name is Paul, being full of the Holy Spirit, looking hard at him, said,

And even with these words, it was hard for them to keep the people from making an offering to them.

Why then are you testing God, by putting on the neck of the disciples a yoke so hard that not even our fathers or we were strong enough for it?

And he departed thence, and entered into a certain man's house, named Justus, one that worshipped God, whose house joined hard to the synagogue.

In every way I showed you that by working hard like this we should help the weak and remember the words that the Lord Jesus himself said, "It is more blessed to give than to receive.'"

And when we were all fallen to the earth, I heard a voice speaking unto me, and saying in the Hebrew tongue, Saul, Saul, why persecutest thou me? it is hard for thee to kick against the pricks.

And when we had gone on slowly for a long time, and had had hard work getting across to Cnidus, for the wind was against us, we went under cover of Crete, in the direction of Salmone;

And, sailing near the side of a small island named Cauda, we were able, though it was hard work, to make the ship's boat safe:

For the hearts of these peoplehave grown callous,their ears are hard of hearing,and they have shut their eyes;otherwise they might see with their eyesand hear with their ears,understand with their heart,and be converted,and I would heal them.