Although there are several senses of the word ‘receive’, the sense intended here, as Matthew Poole comments, seems to relate to the Lord sending out his apostles without a full supply of provisions. Those who see this need and supply it will receive a prophet’s reward.
Here is a powerful incentive for the mutual help and support of one saint towards another. To the extent that we identify in the work that God has given to our fellow believer, we join them in that work and because we work alongside them we share their reward with them. Do we pray for missionaries working in foreign lands? do we send support to them? do we follow their progress with avid attention? To that extent we have some part in their reward. Let us all be striving to advance the Lord’s cause.