Mishkat al-Masabih 296
A man of the B. Sulaim said:
God's messenger counted them in my hand, or in his hand, saying, “The glorifying of God is half the scale,
‘Praise be to God’ fills it, ‘God is most great’ fills the space between heaven and earth, fasting is the half of endurance, and being purified is half of faith.” 

Tirmidhi transmitted it and said that this is a hasan tradition.
وَعَنْ رَجُلٍ مِنْ بَنِي سُلَيْمٍ قَالَ: عَدَّهُنَّ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي يَدِي أَوْ فِي يَدِهِ قَالَ: «التَّسْبِيحُ نِصْفُ الْمِيزَانِ وَالْحَمْدُ لِلَّهِ يَمْلَؤُهُ وَالتَّكْبِيرُ يَمْلَأُ مَا بَيْنَ السَّمَاءِ وَالْأَرْضِ وَالصَّوْمُ نِصْفُ الصَّبْرِ وَالطُّهُورُ نِصْفُ الْإِيمَانِ» . رَوَاهُ التِّرْمِذِيُّ وَقَالَ هَذَا حَدِيثٌ حَسَنٌ