Cast in thy lot among us; let us all have one purse.
Without God's approval unity is nothing. In fact, unless God approves it is treason and sedition. You see, sinners want saints to join their projects and agree with them, but the Lord demands that his children reject and avoid the company of said sinners. The hearts of sinners have very different goals, and they make great appeals for friendship and cooperation.
King Solomon warned all young men, including his son, against the pressure, the peer pressure of sinful men. ( Proverbs 1:10–19 ). They would certainly be destroyed as their golas were murder and robbery. Men who fear the Lord should stay away from them and reject all invitations to join them. Joining them and participating with them, with the gang, brings judgement and is contrary to godliness.
What leads to death and destruction is the broad way and wide gate which has many travellers joined in the majority, happily together. By God King Solomon warned his son that nothing could protect from God's judement, not even combined strength. Not even if it seemed safe to be united with the majority in whatever foolish, sinful behaviour.
In associating with sinners dear reader there is no sanctuary and no safety from judgement. The real sanctuary is a God that delights in your rejection of sinners and of sin. In the Old Testament when nations gathered together against God's church, God knew He would empower His people to destroy them, that's why He mocked them.
Society and fellowship with saints who are godly is wonderful.
What is horrible is when saints are joined together with unbelievers unequally.
What is damnable is fellowship with sinners. Great blessings are unity and community in Christ's churches. However the pressures and invitations of wicked men are hard to resist for men with weak character, even if they are good men.
Only when purity is exalted can God's children have true peace. Purity of righteousness and truth. The holy cry of angels and apostles are, "Come out from among them".
It is demanded from God's highest fellowship and blessings.
Where purity is sacrificed there is no real peace. Only the peace of death.
The men who easily separate themselves from those who do not fear The Lord or who do not keep His commandments are godly men. These men don't need to first pray about the matter, oh no, like Phinehas they end the party by zealously taking a javelin. David hated fools and sinners and he did not want any compromisers near him. ( Psalm 101:3–8 ). For those whom would separate themselves from evildoers he taught God's blessing. ( Psalm 1:1–3 ).
An eternal inheritance in Christ, and the riches in Him, are found only in Canaan, with a separated life. Dear reader, are you willing to go along with Christ Jesus, even if it means to leave everything behind?