Thou shalt rejoice; i.e. either,
1. Thou shalt hereby be enabled to rejoice and take comfort in all thy enjoyments, when thou hast sanctified them by giving God his portion. Or,
2. Thou shalt feast (which is oft expressed by rejoicing) with the Levites and strangers upon the oblations which at these solemn times were offered; which exposition is confirmed by comparing Deuteronomy 16:10 11 14 15.