Isaiah 1:19-20 may be paraphrased this way:

“If you are willing and consequently will obey, you shall eat the good of the land; but if you refuse and consequently will rebel, you shall be eaten by the sword; for the mouth of the LORD has spoken.”

They point back to God’s call for genuine repentance in verses 16-17, and His offer of free cleansing in verse 18. If His people are repentant and would trust in Him alone for cleansing and salvation, then the Lord would protect them from all their enemies and cause them to enjoy peace and blessings in the land that He has given them. But if they remain unrepentant and refuse His gospel call and offer, then God’s covenant judgment and wrath will fall upon them.

Sadly, the Israelites refused God’s offer, and continued to rebel against Him.  “[L]ike Adam they transgressed the covenant… [T]hey dealt faithlessly with” the Lord (Hosea 6:7). Therefore, like Adam, the Lord judged and punished them. They were “eaten by the sword,” and their remnant were taken captive to Babylon (2 Chronicles 36:15-21).

But 2,000 years ago, Christ the new Adam and the new Israel perfectly obeyed God’s word and never rebelled against Him. Through His sinless perfection and obedience He earned all covenant blessings.

Moreover, on the cross, Christ was “eaten by [God’s] sword” and suffered His covenant wrath and curse. Through His death and sacrifice, He paid for our sins of disobedience and rebellion, and purchased for us forgiveness of sins and salvation from God’s judgment and condemnation.

Without Christ, we will all be “eaten by the sword,” doomed to eternal wrath and condemnation. But because of His perfect life, death and resurrection, all true Christian believers are saved from God’s covenant judgment and curse. United to Him by faith, we have become “heirs according to promise” (Galatians 3:29). In Him we have been granted all the covenant blessings that both Adam and Israel failed to achieve. Because of Jesus, we “shall eat the good of the land.”

Meanwhile, as we wait for Christ’s second coming, the Holy Spirit keeps us from refusing and rebelling against God. He makes us “willing” to heed His call to genuine repentance and accept His offer of free cleansing in Jesus. He causes and enables us to grow in Christlike obedience.

Friends, God’s warning is as real as His promise. Refusing and rebellion are to be persistently avoided at all cost. Willingness to heed God’s gospel call and offer is a must.

In Christ, the Lord has mercifully and graciously provided the means for us to

1. be forgiven of disobedience and rebellion, and
2. be enabled and empowered to willingly and persistently turn away from sin and cling to God’s promise of free cleansing in Christ.

Therefore, relying on Christ’s provision and the power of the Holy Spirit, repent. Believe. And by faith, obey.

“… for the mouth of the LORD has spoken.”