Māyāvādīs and atheists accept the forms of the Deities in the temple of the Lord as idols, but devotees do not worship idols. They directly worship the Personality of Godhead in His archa incarnation. archa refers to the form which we can worship in our present condition. Actually, in our present state it is not possible to see God in His spiritual form because our material eyes and senses cannot conceive of a spiritual form. We cannot even see the spiritual form of the individual soul.
When a man dies we cannot see how the spiritual form leaves the body. That is the defect of our material senses. In order to be seen by our material senses, the Supreme Personality of Godhead accepts a favorable form which is called archa–vigraha. This archa–vigraha, sometimes called the archa incarnation, is not different from Him. Just as the Supreme Personality of Godhead accepts various incarnations, He takes on forms made out of matter — clay, wood, metal and jewels.
There are many śāstric injunctions which give instructions for carving forms of the Lord. These forms are not material. If God is all-pervading, then He is also in the material elements. There is no doubt about it. But the atheists think otherwise.
Although they preach that everything is God, when they go to the temple and see the form of the Lord, they deny that He is God. According to their own theory, everything is God. Then why is the Deity not God? Actually, they have no conception of God.
The devotees’ vision, however, is different; their vision is smeared with love of God. As soon as they see the Lord in His different forms, the devotees become saturated with love, for they do not find any difference between the Lord and His form in the temple, as do the atheists. The smiling face of the Deity in the temple is beheld by the devotees as transcendental and spiritual, and the decoration of the body of the Lord is very much appreciated by the devotees.
It is the duty of the spiritual master to teach how to decorate the Deity in the temple, how to cleanse the temple and how to worship the Deity. There are different procedures and rules and regulations which are followed in temples of Vishnu, and devotees go there and see the Deity, thevigraha, and spiritually enjoy the form because all of the Deities are benevolent.
The devotees express their minds before the Deity, and in many instances the Deity also gives answers. But one must be a very elevated devotee in order to be able to speak with the Supreme Lord. Sometimes the Lord informs the devotee through dreams. These exchanges of feelings between the Deity and the devotee are not understandable by atheists, but actually the devotee enjoys them. Kapila Muni is explaining how the devotees see the decorated body and face of the Deity and how they speak with Him in devotional service.
an excerpt from the Srimad-Bhagavatam, Canto 3, Chapter 25, verse 35, purport
By His Divine Grace A.C. Bhaktivedanta Swami Prabhupada