Qitzur Shulchan Arukh – 181:3-4
If they are trying to seize [the disputed amount] and his other litigant is a difficult person, he should drag him to a Jewish court first. If he doesn’t want to come, he should obtain permission from the [Jewish] court, and may avail himself of their [ie non-Jewish] law.
If they are trying to seize money that the person has in hand, he may not avoid settlement [to get the claimant] to retire [his claim], so that the other would more readily come to a compromise and forgive the rest. If he [the defendant] violates [halakhah] and does this, he does not leave Divine [Justice] until he gives him [the one who is owed] what is his.