I'm curious to know exactly what it is to call upon the name of the Lord. I'm sure we'll all agree the best place to find that information would be in God's word.
But before I start my deep dive into the Bible some verses came to mind that I've read before. The first one is about Bartimaeus the blind beggar who called out to Jesus for mercy and healing. The faith of Bartimaeus is seen in how he addresses Jesus as the Son of God. While the crowd tells the blind man to be quiet, Bartimaeus just became louder! When Jesus tells his disciples to bring the blind man over, a miracle happens because of his faith.
Mark 10:46-52 -
And they came to Jericho. And as he was leaving Jericho with his disciples and a great crowd, Bartimaeus, a blind beggar, the son of Timaeus, was sitting by the roadside. And when he heard that it was Jesus of Nazareth, he began to cry out and say, "Jesus, Son of David, have mercy on me!" And many rebuked him, telling him to be silent. But he cried out all the more, "Son of David, have mercy on me!" And Jesus stopped and said, "Call him." And they called the blind man, saying to him, "Take heart. Get up; he is calling you." And throwing off his cloak, he sprang up and came to Jesus. And Jesus said to him, "What do you want me to do for you?" And the blind man said to him, "Rabbi, let me recover my sight." And Jesus said to him, "Go your way; your faith has made you well." And immediately he recovered his sight and followed him on the way.
This one from Jeremiah sounds a lot like salvation.
“Then you will call upon me and come and pray to me, and I will hear you. You will seek me and find me, when you seek me with all your heart.” – Jeremiah 29: 12-13
For me this is an eternal principle and timeless promise - that the Lord is ever near to all who seek Him, and those that search for Him in truth, are certain of finding Him.
Calling on the name of the Lord is basic for salvation and presupposes faith in the Lord. God promises to save those who, in faith, call upon His name: “Everyone who calls on the name of the Lord will be saved” Romans 10:13
And everyone who calls on the name of the LORD will be saved; for on Mount Zion and in Jerusalem there will be deliverance, as the LORD has said, even among the survivors whom the LORD calls. Joel 2:32
Everyone who invokes the name of God for mercy and salvation, by or in the name of Jesus, shall be saved Acts 2:21
“There is salvation in no one else! God has given no other name under heaven by which we must be saved” Acts 4:12