Step 1: Define Saguna Bhakti: 'Saguna' means 'with attributes/form.' Saguna Bhakti saints worshipped God in a specific personal form — e.g. Tulsidas and Surdas worshipped Rama and Krishna respectively, with elaborate iconography, temple worship, and narrative devotion (through epics like the Ramcharitmanas).
Step 2: Define Nirguna Bhakti: 'Nirguna' means 'without attributes/formless.' Nirguna saints like Kabir and Guru Nanak rejected idol worship and caste, emphasizing an abstract, formless, universal God reached through inner devotion and meditation on the divine name.
Step 3: Compare their social approach: Saguna Bhakti generally worked within existing religious structures (temples, epics, caste-linked ritual), while Nirguna Bhakti was more socially radical, directly criticizing caste hierarchy, ritualism, and religious orthodoxy of both Hindu and Islamic establishments.
Final Answer: Saguna Bhakti worships God with form (Rama, Krishna); Nirguna Bhakti worships a formless, attribute-less God and was more socially reformist.