Genesis 15:8

Treasury of Scripture Knowledge

And he said, Lord GOD, whereby shall I know that I shall inherit it?

Abraham said to his servant, the elder of his household who managed all he owned, “Place your hand under my thigh,

Then he said to Him, “If I have found favor in Your sight, give me a sign that You are speaking with me.

If they say, ‘Wait until we reach you,’ then we will stay where we are and not go up to them.

Hezekiah had asked Isaiah, “What is the sign that the Lord will heal me and that I will go up to the Lord’s temple on the third day?”

Show me a sign of Your goodness;
my enemies will see and be put to shame
because You, Lord, have helped and comforted me.

“Ask for a sign from the Lord your God—from the depths of Sheol to the heights of heaven.”

“How can I know this?” Zechariah asked the angel. “For I am an old man, and my wife is well along in years.”