Sforno on Deuteronomy 12:7/ספורנו על דברים י״ב:ז׳

1(1) BEFORE ADONAI YOUR GOD, AND YOU SHALL FEAST. "Worship Adonai in gladness" (Ps. 100:2) as is appropriate for anyone who serves out of love.

2(2) IN ALL YOUR UNDERTAKINGS. For then you will succeed in all your ways and then you will prosper.