SB 10.86.5
ekada grham aniya
atithyena nimantrya tam
sraddhayopahrtam bhaiksyam
balena bubhuje kila
Translation:
One day Lord Balarama brought him to His home as His invited dinner guest, and Arjuna ate the food the Lord respectfully offered him.
Purport:
From the explanation of Srila Visvanatha Cakravarti, it is understood that Arjuna in his sannyasi role had just finished the four-month vows of the rainy season and could now again accept general invitations from householders. Thus no one would have suspected any unusual motive in his visiting Lord Balarama at this time.