sign, proof, reminder

Definition:

A sign is an object, event, or action that communicates a special meaning.

Signs can be reminders of something that was promised:\
- The rainbow God created in the sky was a sign to remind people that he would never again destroy all life with a worldwide flood.\
- God commanded the Israelites to circumcise their sons as a sign of his covenant with them.
Signs can reveal or point to something:\
- An angel told shepherds a sign that would help them know which baby in Bethlehem was the newborn Messiah.\
- Judas kissed Jesus as a sign to the religious leaders that Jesus was the one they should arrest.\
Signs can prove that something is true:\
- The miracles done by the prophets and apostles were signs that proved they were speaking God's message.\
- The miracles that Jesus performed were signs that proved he was truly the Messiah.

Depending on its context, "sign" could also be translated as "signal" or "symbol" or "mark" or "evidence" or "proof" or "gesture."
To "make signs with the hands" could also be translated as, "motion with the hands" or "gesture with the hands" or "make gestures."
In some languages, there may be one word for a "sign" that proves something and a different word for a "sign" that is a miracle.