James 4:14-18

Yet you do not know what your life will be like tomorrow. For you are just a vapor that appears for a little while, and then vanishes away.

Instead, you ought to say, “If the Lord wills, we will live and also do this or that.”

But as it is, you boast in your arrogance; all such boasting is evil.

So for one who knows the right thing to do and does not do it, for him it is sin.