To distinguish between regular occurrence and permanence, Spanish relies on prepositions. The debate surrounding always vs forever spanish centers almost entirely on two phrases: para siempre and por siempre. Without a preposition, siempre tracks actions repeated across time. With a preposition, the phrase converts into a duration marker stretching into an infinite future.
When wedding vows or romantic ballads evoke timeless loyalty, they invoke para siempre. Andrew Lloyd Webber took advantage of this exact emotional resonance when composing the official theme for the 1992 Summer Olympics in Barcelona, titling the bilingual anthem Amigos Para Siempre. As the amigos para siempre meaning demonstrates, the translation isn't "friends always," but "friends for life" or "friends forever."
What about por siempre vs para siempre? The distinction reflects regional variation and poetic weight. While para siempre represents the standard, grammatically rigorous choice across Latin America and Spain to designate a definitive end-point into eternity, por siempre surfaces frequently in literature, religious texts, and songwriting. Think of para siempre as an objective destination ("into forever") and por siempre as duration through time ("throughout eternity").