Although the Buddha gave extensive teachings on developing Vipassana in the many suttas that he gave, he actually used the word Vipassana very rarely. But here is one sutta which he contrasts the purpose of Samatha and Vipassana. This brief sutta is not very widely known and has yet to be included in Access to Insight.
Dve·me, bhikkhave, dhammā vijjā-bhāgiyā. Katame dve? Samatho ca vipassanā ca.
Samatho, bhikkhave, bhāvito kam-attham-anubhoti? Cittaṃ bhāvīyati. Cittaṃ bhāvitaṃ kam-attham-anubhoti? Yo rāgo so pahīyati.
Vipassanā, bhikkhave, bhāvitā kam-attham-anubhoti? Paññā bhāvīyati. Paññā bhāvitā kam-attham-anubhoti? Yā avijjā sā pahīyati.
Rāg·upakkiliṭṭhaṃ vā, bhikkhave, cittaṃ na vimuccati, avijj·upakkiliṭṭhā vā paññā na bhāvīyati. Iti kho, bhikkhave, rāga-virāgā cetovimutti, avijjā-virāgā paññāvimuttī.
These two things, bhikkhus, are conducive to knowledge. Which two? Samatha and vipassanā.
By developing Samatha, bhikkhus, what purpose is served? Mind is developed. By developing the mind, bhikkhus, what purpose is served? Whatever passion there is is abandoned.
By developing vipassanā, bhikkhus, what purpose is served? Wisdom is developed. By developing wisdom, bhikkhus, what purpose is served? Whatever ignorance there is is abandoned.
Defiled by passion, bhikkhus, the mind is not released, and defiled by ignorance, wisdom is not developed. Thus, bhikkhus, with the fading of passion there is liberation of the mind, with the fading of ignorance there is liberation by wisdom.