Life has meaning in light of eternity. It is because of that which is eternity that life has meaning.
Merely believing in Eternity is perhaps enough for some but not for all. If you don’t think that a suicide bomber fits the bill, then look no further than your Bible. Have you read Ecclesiastes? Anyone who thinks that the religious are immune to nihilism and that nihilism is only an atheist concern ought to read it. Solomon appears to have had a very pessimistic view of the human condition but by the end of the book resolves to endure and even triumphs in the manner of Sisyphus pushing the rock up the mountain again and again. Note that Solomon struggled no less for being a theist in getting to that point of triumph.
Ecclesiastes 1
1 The words of the Teacher, [a] son of David, king in Jerusalem:
2 “Meaningless! Meaningless!”
says the Teacher.
“Utterly meaningless!
Everything is meaningless.”
3 What does man gain from all his labor
at which he toils under the sun?
4 Generations come and generations go,
but the earth remains forever.
5 The sun rises and the sun sets,
and hurries back to where it rises.
6 The wind blows to the south
and turns to the north;
round and round it goes,
ever returning on its course.
7 All streams flow into the sea,
yet the sea is never full.
To the place the streams come from,
there they return again.
8 All things are wearisome,
more than one can say.
The eye never has enough of seeing,
nor the ear its fill of hearing.
9 What has been will be again,
what has been done will be done again;
there is nothing new under the sun.
10 Is there anything of which one can say,
“Look! This is something new”?
It was here already, long ago;
it was here before our time.
11 There is no remembrance of men of old,
and even those who are yet to come
will not be remembered
by those who follow.