'Sign' in the Bible

This will be a confirming sign for you that will be fulfilled through your two sons, Hophni and Phinehas: in a single day they both will die!

Then Samuel took a small container of olive oil and poured it on Saul's head. Samuel kissed him and said, "The Lord has chosen you to lead his people Israel! You will rule over the Lord's people and you will deliver them from the power of the enemies who surround them. This will be your sign that the Lord has chosen you as leader over his inheritance.

But if they say, 'Come up against us,' we will go up. For in that case the Lord has given them into our hand -- it will be a sign to us."