die Oase
oasis
A fertile place in a desert where there is water and plants.
Nach einem langen Marsch erreichte die Karawane endlich eine Oase.
After a long march, the caravan finally reached an oasis.

oasis
Loading your saved state.
oasis
A fertile place in a desert where there is water and plants.
Nach einem langen Marsch erreichte die Karawane endlich eine Oase.
After a long march, the caravan finally reached an oasis.

The figurative meaning is very common and often follows the pattern 'eine Oase der/des' + noun in the genitive. This describes the type of relaxation more precisely.
Nach der lauten Party war ihr ruhiges Zimmer eine Oase des Friedens.
After the loud party, her quiet room was an oasis of peace.
You can recognize the literal meaning from the context of deserts, water scarcity, and travel. The figurative meaning refers to any quiet place in a hectic environment such as a city or an office.
Die Beduinen kannten den Weg zur nächsten Oase genau.
The Bedouins knew the way to the nearest oasis exactly.
With 'Oase' (oasis), the preposition 'in' is used. To describe a location, use the dative ('in der Oase' — in the oasis). To express movement toward it, use the accusative ('in die Oase' — into the oasis).
Wir machten eine Pause in einer schattigen Oase.
We took a break in a shady oasis.
source
'die Quelle' and 'die Oase' can both have to do with water or with something positive. In nature, a Quelle is the place where water comes out of the ground. An Oase is a fertile place in the desert where there is water and plants. So an Oase can have a Quelle, but it is not the same thing. In a figurative sense, a Quelle is more the origin or cause of something, while an Oase is more a place of peace. Learners may confuse the words if they only think of water or relaxation. The important point is: 'Quelle' emphasizes the origin, while 'Oase' emphasizes the pleasant place.

Der kleine Garten ist für die Familie eine Oase mitten in der Stadt.
The small garden is an oasis in the middle of the city for the family.
Nach der Wanderung füllten wir unsere Flaschen an einer klaren Quelle.
After the hike, we filled our bottles at a clear spring.