When the Israelites crossed the Jordan River God instructed Joshua to select 12 men (one to represent each tribe), who were tasked with each gathering a stone from the dry riverbed of the Jordan – Joshua 4:1-7 (https://bit.ly/3bpEiQr). Why? In years to come the stones would help the Israelites remember the miracle of what God had done for them on that day.
The cross is our memory. The symbol of a cross reminds us of the miracle of God’s sacrifice and forgiveness.
Done something wrong recently. Feeling guilty about something. Not proud of something you said. Look at a cross and remember.