Sayyiduna Abu Hurayrah (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Whoever performs ablution and does it well, then comes to Jumu'ah, sits silently near the imam and listens attentively to the sermon, his sins from one Jumu'ah to the next, and three more days besides, will be forgiven; and touching the pebbles is idle talk."
This contains evidence that ablution suffices in place of the Friday ritual bath (ghusl).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5849