Muwatta Malik · Hadith 1638

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّهُ قَالَ بَلَغَنِي أَنَّ الْمَرْءَ، لَيُدْرِكُ بِحُسْنِ خُلُقِهِ دَرَجَةَ الْقَائِمِ بِاللَّيْلِ الظَّامِي بِالْهَوَاجِرِ ‏.‏

Yahya related to me from Malik that Yahya ibn Said said, "I have heard that by his good character a man can reach the degree of the one who stands in prayer at night and the one who is thirsty from fasting in the heat of the day

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).