Hold up a cell phone and ask if anyone has ever used one. Ask them to name places where they've used a cell phone. Answers may include in a car, outside, in the house, even on a boat.
Now ask the class why they have used a cell phone. Answers may include I needed information, when I needed help, when I may be lost and not know directions, or when I just want to talk to someone.
Briefly relate a few instances of when you use your own cell phone.
Ask the students, "Can you just call any number to reach my cell phone?" (No, you must know the correct phone number.)
Tell the students, "Did you know God wants us to call Him? He even gives us a way to call him -- prayer -- and His number."
We can't just call any number and reach God. Jesus said in John 14:6, "I am the way and the truth and the life. No man comes to the Father but by me." There is no other way to call on God except through Jesus Christ, His Son. When we pray, we must pray in the name of Jesus Christ.
We can use our cell phone (prayer) to call on Heavenly Father anytime and anywhere. Read Alma 34: 17-27.
We can have a phone, we can know someone's number, but until we choose to actually dial the number, we'll never reach them. It's our choice to call on God; we must act upon our choice by praying. Heavenly Father is there anytime, anywhere and for anyone. Close with D&C 88:63.
