22 Do you have faith? Have it to yourself before God. Happy is he who does not condemn himself in what he approves. 23 But he who doubts is condemned if he eats, because he does not eat from faith; for whatever is not from faith is sin. (Romans 14:22–23, NKJV)
The personal “faith” of which Paul speaks here, is one’s personal confidence (trust) of conscience to participate in a God-approved liberty. Paul adds a warning not to violate one’s conscience in using these liberties: “But he who doubts is condemned if he eats, because he does not eat from faith; for whatever is not from faith is sin” (v. 23). His exhortation and warning about one’s conscience and God-allowed liberties agrees with his earlier statement, “Let each be fully convinced in his own mind” (Romans 14:5). Today’s passage is not at all suggesting that every person decides for himself what is sin, and what is not. God sets that standard, and when we violate it, we sin (John 17:17; 1 John 3:4; Romans 3:23). Before we engage in an activity, we must be sure from Scripture that it has God’s approval (1 Thessalonians 5:21-22; 2 Timothy 3:16-17). In matters of liberty (a God-allowed, but not compulsory, action), our conscience must be clear. We must not violate our conscience in these liberties, nor force our conscience upon others (Romans 14:13-16).