Numbers 32:22
And the land be subdued before the LORD: then afterward ye shall return, and be guiltless before the LORD, and before Israel; and this land shall be your possession before the LORD. And the land be subdued before the LORD: then afterward ye shall return, and be guiltless before the LORD, and before Israel; and this land shall be your possession before the LORD.
The tribes of Gad and Reuben were permitted to settle east of the Jordan only on condition that they first cross over and fight alongside the rest of Israel until Canaan was subdued. Only after that shared campaign was completed would they be guiltless before the Lord and before Israel and entitled to return to claim their chosen land as their possession. To break that promise and withhold their help would itself be sin against the Lord, a sin that would not remain hidden but would be exposed and would find them out. In the same way, seeking personal ease and prosperity while leaving fellow believers to carry the hardships and responsibilities of the church brings guilt rather than guiltlessness, for God sees all neglect, selfishness, and evasion and visits it with judgment.