Romans 14:3-4 — Let not him that eateth despise him that eateth not; and let not him which eateth not judge him that eateth: for God hath received him.
Who art thou that judgest another man's servant? to his own master he standeth or falleth. Yea, he shall be holden up: for God is able to make him stand.
The strong shouldn't despise the weak for not eating, the weak shouldn't judge the strong for eating.
Don't criticize about matters not covered in Scripture.
God hath received him — at salvation, by faith in Christ
Verse 4 is speaking to the weak.
Stand or fall — remain upright or sin in using liberty
The believer stands in Christ's power, not his own.
Liberty (without law) without the power of Christ will result in falling.
Galatians 5:13 — You, my brothers, were called to be free. But do not use your freedom to indulge the sinful nature; rather, serve one another in love.