Numbers 32:21

And will go all of you armed over Jordan before the LORD, until he hath driven out his enemies from before him,

Gad and Reuben promised to go armed across the Jordan with the rest of Israel into battle and to remain with them until the inheritance was received. The verse establishes the duty not to avoid the shared conflict while seeking a settlement for oneself. Christians likewise must not seek ease while leaving others to carry the work and hardship of the church, but must take part in the struggle for truth and the conversion of sinners.