The second evidence presented to support the return of Christ is the Holy Scripture, specifically the prophecies about the day of the Lord (2 Peter 3:10). Mention is made of this day on several occasions in the Old Testament. It was strongly tied with the coming of the Messiah and presented as a time when God would right all wrongs. Given the fact that the first coming of Christ has affirmed many promises of Scripture, Christians have every reason to believe that promises about his second coming will also be realized.
Peter presents these Old Testament prophets as lights in a dark place. They testify to the coming of a dawn and prepare us for Christ’s future return. They can and must also be trusted because the men who wrote the Holy Scripture were inspired by the Holy Spirit. They did not speak what they desired but were led by the Spirit of God.
The Reformed Confessions articulate what the Bible teaches us about its inspiration and why we should trust it completely:
Belgic Confession Article 3: The Word of God
We confess that this Word of God did not come by the will of man, but that men spoke from God as they were carried along by the Holy Spirit, as the apostle Peter says (2 Peter 1:21). Thereafter, in his special care for us and our salvation, God commanded his servants—the prophets and apostles—to commit his revealed Word to writing (Exodus 34:27; Psalm 102:18; Revelation 1:11, Revelation 1:19) and he himself wrote with his own finger the two tables of the law. (Exodus 31:18). Therefore we call such writings holy and divine Scriptures (2 Timothy 3:16).
Belgic Confession Article 5: The authority of Holy Scripture
We receive all these books (1 Thessalonians 2:13), and these only, as holy and canonical, for the regulation, foundation, and confirmation of our faith (2 Timothy 3:16–17). We believe without a doubt all things contained in them, not so much because the church receives and approves them as such, but especially because the Holy Spirit witnesses in our hearts that they are from God (1 Corinthians 12:3; 1 John 4:6; 1 John 5:7–8), and also because they contain the evidence of this in themselves; for even the blind are able to perceive that the things foretold in them are being fulfilled (Deuteronomy 18:21, Deuteronomy 18:22; 1 Kings 22:28; Jeremiah 28:9; Ezekiel 33:33).
19 And we have the prophetic word more fully confirmed, to which you will do well to pay attention as to a lamp shining in a dark place, until the day dawns and the morning star rises in your hearts,