As for the one who is weak in faith, welcome him, but not to quarrel over opinions.
It is important to note and remember that Paul is referring to matters of opinion. The context relates to practices in a believer’s life that are not driven by scriptural command. We are never to pass judgement on others in the area of opinion and personal choice. Judgement must be carefully weighed and humbly applied to brothers and/sisters in Christ only in matters clearly covered by Scripture. Some things are clearly wrong and must be judged. Some things are clearly opinion and must be tolerated. The tension between the two must be maintained in humility.
Romans 14:10-12
But as for you, why do you judge your brother or sister? Or you as well, why do you regard your brother or sister with contempt? For we will all appear before the judgment seat of God. For it is written:
“AS I LIVE, SAYS THE LORD, TO ME EVERY KNEE WILL BOW,
AND EVERY TONGUE WILL GIVE PRAISE TO GOD.”
So then each one of us will give an account of himself to God.
1 Corinthians 5:12-13
For what business of mine is it to judge outsiders? Do you not judge those who are within the church? But those who are outside, God judges. REMOVE THE EVIL PERSON FROM AMONG YOURSELVES.