The fountainhead of faith is honesty.

ثلاثٌ مَن كُنَّ فيهِ كَمُلَ إيمانُهُ : العقلُ ، والحِلْمُ ، والعِلمُ . ح: 4658

Three attributes, when present in an individual, complete his faith: intellect, clemency and knowledge. H: 4658

المؤمنُ غِرٌّ كريمٌ ، مأمونٌ على‏ نفسِهِ ، حَذِرٌ مَحزونٌ . ح: 1901

The believer is gullible and kind, secure from his own [lower] self, yet wary and distressed [on account of it]. H: 1901

المؤمنُ مَن وَقى‏ دِينَهُ بدُنياهُ ، والفاجرُ مَن وقى‏ دُنياهُ بدِينِهِ . ح: 2160

The believer is he who protects his religion by putting his world at stake, whereas the impudent one is he who protects his worldly affairs by putting his religion at stake. H: 2160

أفضلُ المؤمنينَ إيماناً مَن كانَ للَّهِ أخْذُهُ وعَطاهُ وسَخطُهُ ورِضاهُ . ح: 3278

The best of believers in terms of faith is he whose giving and withholding, and whose displeasure and pleasure are solely for Allah. H: 3278

الإيمانُ إخلاصُ العملِ . ح: 873

Faith is sincerity of action. H: 873

لا يَكْمُلُ إيمانُ عبدٍ حتّى‏ يُحِبَّ مَن أحَبَّهُ اللَّهُ سبحانه ، ويُبغضَ مَن أبْغَضَهُ اللَّهُ سبحانَهُ . ح: 10849

A servant's faith is not complete until he loves one whom Allah, the Glorious, loves and hates one whom Allah, the Glorious, hates. H: 10849

أفضلُ الإيمانِ حُسنُ الإيقانِ . ح: 2992

The best of faith is excellent conviction. H: 2992

حُسْنُ العَفافِ والرِّضا بالكَفافِ مِن دعائمِ الإيمانِ . ح: 4838

Excellent chastity, and satisfaction with the bare necessities are among the pillars of faith. H: 4838

رأسُ الإيمانِ الصِّدقُ . ح: 5222

The fountainhead of faith is honesty. H: 5222

آفةُ الإيمانِ الشِّركُ . ح: 3915

The bane of faith is polytheism idolatry. H: 3915