Sa Taya Shraddhaya Yuktah

In 7.21, Krishna said He strengthens every devotee's faith. Here He completes the picture: armed with that faith, the devotee worships and receives the desired results. But the real source of those results is Krishna Himself.

Think of it this way. Many different light bulbs hang in a room — each one looks distinct, each gives a different color or intensity. But the electricity running through all of them comes from one source. Similarly, whatever deity a devotee worships and whatever blessings they receive, the ultimate power granting those blessings is always the one divine.

This shloka does not call any form of worship futile. The fruits do come. But the next shloka (7.23) will add one crucial detail: those fruits are finite.

Shlokas 7.21, 7.22, and 7.23 form a three-part unit: faith is steadied, fruits are received, but those fruits are limited. This is an analysis of the depth and destination of different forms of devotion.

The Vishnu Purana states that the Lord dwells as the inner controller (antaryami) within all deities. The Gita's 'mayaiva vihitan' — ordained by Me alone — is a statement of that same antaryamitva.