The believer who is weak in faith is slave to his/her personal principles and preferences. He submits himself to extra-Biblical rules, and judges anyone who does not ascribe to his subjective standard of holiness.
We are not to quarrel with such saints. Instead, each of us is to should be keen to discern the difference between our subjective opinions, and God’s true standards which are found only in the Word.
To judge, as Paul uses the term in our text, and the way Jesus uses it in Matthew 7:1, is to evaluate the holiness of another based on subjective standards.
We need not question the salvation of the weaker brother/sister just because the one exhibits greater freedom and the other is restricted from enjoying their lives. Instead we are to accept one another because God has accepted each of us.
The one who is strong in faith does not adhere to superstition and does not bow to the opinions of men. He/she is submitted to the Word of God. And in things where God has not promoted or prohibited, she feels to free to approach those things without concern of heaven’s recourse.
Strong faith in God tends to freedom. Weak faith leaves room for fear. But whether weak or strong, God loves and accepts those who desire to honor Him. He shows grace and patience to those who are not yet able to trust Him more fully.