إِنَّ الطَّرِيقَ طَوِيلٌ، وَلَكِنَّ الْخُطْوَةَ الْأُولَى قَرِيبَةٌ.
The road is long, but the first step is near.
The first clause acknowledges difficulty; the second, introduced by lakinna, checks a despairing inference and makes beginning seem attainable. The function is motivational, not merely decorative contrast.
“Long” and “near” are not a neat lexical antonym pair in this setting; they qualify different things, the whole journey and its first step. The discourse contrast is more securely described than a forced textbook antithesis.