Those who believed, emigrated, and strove with their possessions and lives in the Cause of Allah, as well as those who hosted them and supported them (in Madinah), are close protecting friends of one another. For those who believed but stayed back (in Makkah), you don't owe them support until they migrate. However, if they seek your help as sisters and brothers in DEEN (Divine Ideology), then it is your duty to help them except against a folk with whom you have a treaty. Allah is fully Aware of all your actions.