While Matthew 7:1 is the go-to text for the biblically illiterate everywhere, and only the first two words at that, fewer texts are more abused among shallow thinking Christians than Matthew 18:20.
Ten times out of nine (yes, you read that correctly), this verse is used in reference to the worship of God. One line of thought is to comfort those who of necessity must worship in extremely small groups.
However, the far greater use of the text is by those who wish to excuse themselves from the assemblies of the saints in order to pursue worldly pleasures.
This thinking might manifest itself in someone who decides to go hunting or fishing on the Lord’s Day but can’t be bothered to interrupt his excursion to worship with the saints. Taking 10-15 minutes of his time to read his Bible, pray. and, provided he remembered to bring them, partake of the elements of the Lord’s Supper satisfies his shallow conscience that he has fulfilled his obligation to worship. I have also seen college students “worship” during the wee hours of Sunday morning, seeing as they are still awake after midnight, so that they might sleep in on Sunday morning.
These latter misuses manifest a profound misunderstanding of worship. But to the point at hand, it reveals a total lack of understanding of context wherein the original text is found.
As we have noted repeatedly mentioned in this brief (thus far) study, context is critical to a proper understanding of any text. The context of Matthew 18:20 begins in verse 15, and the only subject under consideration is the reconciliation between estranged brethren and the ultimate action to be taken against unrepentant brethren.
Note that our text immediately follows the command to separate ourselves from the unrepentant. Consider also that in at least two other similar texts (1 Cor 5:1-5, 2 Thes 3:6), the name of Jesus is invoked to confirm Divine approval of said action. Matthew 18:20 concerns church discipline, not worship.