When I was a kid, there was one rule that everyone in the neighborhood abided by: If Mom calls, you better come running. We were free to ride bikes and play baseball and explore the woods, but we needed to stay within earshot of home. When Mom called, we were expected to answer.
The type of calling in this verse is a different type of calling. The phrase call on the name in Greek, is epikaleomai onoma, (eh-pee-call-eo-ma-hee). Kaleo means to cry out. It means to appeal to someone. It is a cry for help that requires humility and submission. There is a respect, reverence and recognition of authority in this type of calling.
Imagine if one of us kids got hurt while playing in the woods and needed help. If we were within earshot, then we could cry out for help and Mom, or Dad if he was home from work, would have come running. But what if we were up to something we shouldn't have been and were afraid of getting caught, but really needed help? Like, the time a certain principal's son accidentally set the woods on fire. We might have been afraid of the consequences if we had done something wrong, but help was only coming from one place, our loving parents.
We have a Father in heaven who is always within earshot of our cries for help and he already knows what we've done and the trouble we've gotten ourselves into. In fact, it's as if He is already calling our name to come home, holding out a helping hand toward us, ready to pick us up. God is ready to forgive and earnestly desires to help. But make no mistake, God expects an answer and a refusal to respond will result in punishment. The Bible tells us that God is calling all people everywhere to repent and that if we hear His voice, we shouldn't harden our hearts and ignore him, we should answer. (Acts 17:30, Romans 10:21, Hebrews 3:15)
All of us have gotten into trouble in this life. At some point, we are all spiritually sick, beaten down, sinful and in need of help. Calling upon the name of the Lord is our response to His call out to us. The word epikaleomai means to receive and invite his name. When we cry out to God we are asking, desperately appealing, to be called by his name, willingly choosing to become His child and to be saved and received as His own. Calling on the name of Jesus is our way of admitting we need help and receiving Him as our Savior. Our action is the crying out. His action is the rescuing.
Here is a link to another article I wrote on why we ask Jesus into our hearts: http://thetrustworthyword.blogspot.com/2017/07/why-do-we-ask-jesus-to-come-into-our.html