How do we know that God's salvation is conditioned upon Christ?

The concept that salvation is conditioned on Christ is supported by numerous scriptural references. God has instituted a covenant of grace, where all blessings and benefits come through Christ alone, as He fulfilled every condition of the law. Hosea's prophetic imagery emphasizes that there is no possibility for salvation through our own works; if it were reliant on us, it would certainly fail. The whole narrative of Hosea points to the necessity of Christ's atonement, making clear that all of God's promises find their 'Yes' in Him, ensuring the salvation of all whom the Father has given to Him.