Analysis:

This quatrain by Saadi Shirazi expresses a deep longing and devotion to a loved one. Let's break down its meaning:

The Beloved's Presence: When the beloved is present, the poet finds peace and comfort. Their presence is seen as a source of grace and kindness.
The Beloved's Absence: Even when the beloved is absent, their memory and influence pervade the poet's surroundings. The poet seeks their presence in everything they see.
The All-Encompassing Love: The love expressed is so profound that it permeates the poet's entire world. They see their beloved's influence in every aspect of their life.

Themes:

Love and longing: The central theme is the poet's deep love and longing for their beloved.
The beloved's presence: The beloved's presence is seen as a source of peace and comfort.
The power of memory: Even in the beloved's absence, their memory is a powerful force.
The all-encompassing nature of love: Love is depicted as a force that permeates every aspect of the poet's life.

Deeper Meaning:

This quatrain beautifully captures the intensity of love and the profound impact a beloved can have on one's life. The poet's ability to see their beloved's presence even when they are absent suggests a deep connection and a love that transcends physical presence.

This quatrain is a celebration of love and devotion. It reminds us of the enduring power of love and the ability of our loved ones to shape our world, even when they are not physically present.