Why should Christians not rely on their merits?

In Exodus 19, God clearly states that humanity cannot merit His favor or presence; the law serves to highlight this truth. When the Israelites chose to say they would keep God's law, they demonstrated their ignorance of their inability to truly fulfill it. Relying on our merits leads to self-righteousness and places us in a position of judgment before God, which ultimately results in condemnation. Instead, acknowledging our inability and leaning on God's grace enables us to receive forgiveness and approach God confidently through Christ, who has secured our acceptance.