In Romans 1:9, Paul also calls God as his witness, reinforcing his sincerity—here for his constant prayers. Both verses appeal to divine witness for truthfulness.

In Romans 10:1, Paul's prayer for Israel's salvation directly flows from the truthfulness and sorrow he asserts here.

2 Corinthians 1:12 also appeals to the testimony of conscience as Paul does here, linking truthful behavior to divine grace.

In 2 Corinthians 1:23, Paul again calls God as witness to his motives, similar to his strong assertion of truth here.

In 2 Corinthians 11:31, Paul declares that God knows he is not lying—a direct parallel to the 'I am not lying' claim here.

In Galatians 1:20, Paul writes 'I assure you before God that what I am writing you is no lie'—virtually identical to the truth claim here.

In Philippians 1:8, Paul calls God as witness to his deep affection—another instance of invoking divine witness for his sincerity.

In 1 Thessalonians 2:5, Paul says 'God is our witness' regarding his pure motives, closely matching the appeal to divine witness here.

In 1 Timothy 2:7, Paul explicitly says 'I am telling the truth, I am not lying'—a direct verbal parallel to the claim in this verse.

John 1:11 notes Jesus was rejected by His own — this explains the cause of Paul's sorrow for Israel, which he introduces with his truthful declaration.

In Acts 24:16, Paul strives for a clear conscience, directly paralleling his claim that his conscience confirms his truthfulness in Romans 9:1.

Job 16:19 appeals to a heavenly witness for his integrity—parallel to Paul's conscience witnessed by the Holy Spirit.

In Jeremiah 17:16, the prophet similarly declares his sincerity before God — both appeal to God's knowledge of their truthful ministry.

In 2 Corinthians 11:10, Paul similarly invokes 'the truth of Christ' to affirm his sincerity, paralleling his oath-like statement.

In 2 Corinthians 12:19, Paul emphasizes speaking in the sight of God as those in Christ, echoing the solemn sincerity of his statement here.

In 2 Timothy 1:3, Paul's 'clear conscience' mirrors his 'conscience bears me witness' here, reinforcing sincerity.