How do we know the gospel will be successful?

The success of the gospel is guaranteed by God's own promise. Isaiah 55:11 states that God's word will accomplish what He intends and will not return void. This certainty is rooted in the sovereignty of God, who has ordained the preaching of the word as the means by which He will save His people. Just as God provided the victory at Jericho before the battle even began (Joshua 6:2), the gospel's success is certain because it is God's work, not ours. The Lord of hosts fights for us, and He ensures that His chosen will hear and respond in faith through the preaching of the gospel.