<p>In <em>Acts 2:21</em>, when <em>Peter</em> is addressing the crowd gathered in Jerusalem on the day of Pentecost, Peter tells them about the fulfillment of the prophecy <em>of Joel</em>, which promised that God would pour out <em>His Spirit</em> on all flesh, and informs them that <em>Jesus</em>, whom they crucified, was raised by God and exalted to His right hand.</p>
<p>Peter then calls them to repent of their sins and be baptized in the name of Jesus Christ for the forgiveness of their sins and to receive the gift of the Holy Spirit. It is in this context that he quotes the verse in question, which is a reference to the book of the prophet <em>Joel (2:32)</em>.</p>
<p><strong>Theological and practical significance</strong></p>
<p>The <em>&ldquo;calling on the name of the Lord&rdquo;</em> in this verse is an invitation to turn to God for salvation. When Peter says this, he is calling on the crowd to turn to God for help, in this case, for help in salvation.</p>
<p>It is clear that salvation is <em>only possible through Jesus Christ</em>. That is, when we call upon the name of the Lord, we call upon Jesus to save us from our sins. Sent into the world as <em>the Savior</em> of mankind, Jesus came to earth to redeem us by His sacrifice. And when we ask God for salvation, He grants it to us through what Jesus did for us on the cross.</p>