Looking for some sources as to what induces a person to become more devoted in his service of God.
I have read about certain big tzadikim who devoted themselves with extreme mesirut nefesh (efforts) and was wondering from where does this desire come from.
For example, the Rambam in Mishne Torah yesodei tora ch.2 says this desire comes from examining the wisdom in nature.
What is the path [to attain] love and fear of Him? When a person contemplates His wondrous and great deeds and creations and appreciates His infinite wisdom that surpasses all comparison, he will immediately love, praise, and glorify [Him], yearning with tremendous desire to know [God's] great name, as David stated: "My soul thirsts for the Lord, for the living God"
are there other sources that discuss what induces a person to this strong devotion? and why should that approach be the most powerful one.