In rāgānugā bhakti we naturally love Kṛṣṇa, having a strong desire to serve Him. Indeed, it has been shown that God is personal and exceedingly beautiful. The sages such as Vyāsa have seen that beauty through the eyes of their soul, and having described it they have outlined the form of the Deity.
He is identical with this extremely lovely form. His perfect personality exists eternally in the spiritual world and at the same time in each object and place created by Him. He who perceives the spiritual form of the Deity with the vision of the soul, carries this impression in the profoundest of his heart, satisfying his material vision.
The Deity worship is very important because the world attracts us through the senses, and if we don't see God in the sense objects, it will prove more difficult to advance spiritually. If we bring a Deity to our home, we need to know that we have the Supreme Person with us, and offering Him food and then taking His remnants as His prasādam (mercy), we have to strive for His wellbeing and satisfaction, getting wholly involved in it.
We can also offer Him sandalwood, perfumed flowers, ghee lamp, incense, etc which can later be accepted as prasādam as well. In this way our eyes, ears, nose, sense of touch and tongue, indeed all of our senses will be getting spiritualised up to the point where we will serve Him with a pure heart.
At the time of dīkṣā we agreed to surrender ourselves to Guru/Kṛṣṇa, and by performing the worship of our beloved deity we confirm the meaning of that voluntary surrender which we did out of love for Him. In fact, due to His mercy which He gives us by manifesting His form, we can associate with Him more consciously, we can see, touch and serve Kṛṣṇain His form of Śrī Ṭhākurjī Who gives Himself to His devotees.
"My friend, if you still wish to enjoy the company of your mundane friends and family members, do not look at the the form of Hari called Govinda standing near Keśi-ghāṭa. Casting crooked glances with His eyes, He has a flute
put on His bud-like lips, and His body bent at three places
is illuminated by the light of the Moon."
"If a person of pure mind offers Me with love and devotion a leaf,
a flower, a fruit or water, I accept it."