We consider the effectual call of God - that process by which God applies to His people all the benefits of what Christ accomplished for them in His life and His death on the cross.
We reflect on our deadness apart from Christ - our total lack of desire for Him and our inability to come to Him for salvation. It is this deadness that makes the effectual call necessary. The Holy Spirit transforms our hearts so that we become willing to come to Christ. Whilst many hear the outward call of God, without this inward and effectual call, no-one will respond in repentance and faith.
We see how totally dependent we are on God for our salvation - and for the salvation of others when we reach out to them with the Gospel.