1. SAGUN BHAKTI: With five senses dedicated to god: hymns,
with heart, ask god's help
2. NIRGUN BHAKTI: Worship with knowledge: with mind; when
the senses tempt us to do wrong, we should fight against it, to
become positive.
We can worship God with our five senses (Sagun Bhakti) or with knowledge (Nirgun Bhakti).
Sagun Bhakti is worshiping the God with the five senses, by dedicating these senses and their activities including worshiping to the God. It implies we speak good, we hear no evil, and we see with noble eyes excluding any immoral lust etc. It is worshiping the God with the heart using the five senses. It is not knowledge based or logic based. Reciting God's name or hymns (even without understanding the meanings as most of us do at present) is part of Sagun Bhakti.
Idol worship also falls in the same category; but remembrance it is not an end by itself. Some of us believe in idol worship and others think it is an immoral practice. This contradiction is the cause of many a battle in human society, both views can be right. However if Sagun Bhakti is an end by itself, then there is a flaw in it. An idol is an aid to worship the God; it is not the God, as perceived by a vast majority. To believe in, idol worship or other rituals (which we do using our five senses) may be good for a beginner but we must graduate to 'nirgun bhakti' as we grow. The advantage of idol worship/Sagun Bhakti is that it is an easy way to visualize God, similar to the way we remember our late parents with photographs.
But we must ensure that we graduate ourselves from Sagun Bhakti to Nirgun Bhakti i.e. worshiping God logically with knowledge or mind . However in our society, there is less emphasis on correct behavior as ordained by God and more emphasis is on the rituals etc. In Nirgun Bhakti the five senses are considered to be an obstacle to worshiping, as all the evil in the world emanates due to our never ending efforts to satisfy the ever hungry five senses. It thinks of social welfare as a means to remember and pray God.
The ideal combination is that we start with Sagun Bhakti and finally complement with Nirgun Bhakti and only then it will result in complete harmony in the society.
In the end Sagun Bhakti implies: the five senses dedicated to God, worshiping with heart, remember God with hymns and is easy to follow, as we depend on God's blessings to worship effectively. Nirgun Bhakti implies: five senses are the cause for temptations that obstruct us, it is worshiping with mind, thinks of God in social welfare, dependson self thus needs disciplined approach.