BAYHAQI 3585:
from Jābir b. ʿAbdullāh —
[Machine] The Prophet ﷺ went out and said, "O people, beware of showing off in secret actions." They said, "O Messenger of Allah, what is the showing off in secret actions?" He said, "When a person stands to pray and beautifies his prayer eagerly because of what he sees from the people looking at him, that is showing off in secret actions."
البيهقي ٣٥٨٥:
عن جابر بن عبد الله —
خَرَجَ النَّبِيُّ ﷺ فَقَالَ أَيُّهَا النَّاسُ إِيَّاكُمْ وَشِرْكَ السَّرَائِرِ قَالُوا يَا رَسُولَ اللهِ مَا شِرْكُ السَّرَائِرِ؟ قَالَ يَقُومُ الرَّجُلُ فَيُصَلِّي فَيُزَيِّنُ صَلَاتَهُ جَاهِدًا؛ لِمَا يَرَى مِنْ نَظَرِ النَّاسِ إِلَيْهِ فَذَاكَ شِرْكُ السَّرَائِرِ
hadithunlocked.com