Charles Spurgeon Commentary Deuteronomy 15:3

"Of a foreigner thou mayest exact it: but whatsoever of thine is with thy brother thy hand shall release." — Deuteronomy 15:3 (ASV)

How was a man to pay when he did not sow or reap during the Sabbatical year? The foreigner did not observe the year of rest; consequently he was bound to pay, and it was only fair that he should do so; but for the Israelite, who carried out the divine law, there was provision made if he was in debt.