O: God wants to Isrealites to remember that he brought them out of Egypt with a strong hand. It is mentioned twice about them having a sign on the hand a reminder or pendant on their forehead, so that they may always remembered God is with them.
A: Different people wear different signs to remember things. Some people get permanent tattoos in rememberance of a loved one. Married couples wear a ring as a symbol and to remind them of their vows. Some people wear crucifix or medallion to remind them of God. Here, God is asking us to put his word on our forehead, at the front of our thought process, that we might keep from letting evil desires come into our mind. He wants us to always have his word at the forefront of our thoughts to help prevent us from sin.
K: Lord, I pray to always keep you in my mind and on my hands to prevent my mind and hands from allowing desires into my mind and my hands to act on them. Help me keep you in my thoughts to prevent me from sin, Amen.