Paul stated, “Do not be unequally yoked together with unbelievers. For what fellowship has righteousness with lawlessness?” (2 Corinthians 6:14 NKJV). Paul indeed had Deuteronomy 22:10 (NKJV) in mind, which says, “You shall not plow with an ox and a donkey together.” It is possible to bind these two animals together, but it only causes problems-so the Law forbade it. For the same reason, you should not bind yourself together with an unbeliever.
Do two walk together unless they have agreed to do so? Amos 3:3 NIV
When we look at the opposite side, Christians have difficulty working as one together with other fellow believers. In this verse, God makes the point that two travelers will not walk together unless they have agreed to do just that. These two must remain in agreement, or they will ultimately cease walking together. Paul said the the Philippians that he had hoped to hear that they were standing “fast in one spirit, with one mind striving together for the faith of the gospel” (Philippians 1:27 NKJV).