It is indeed true because faith, as an inward quality, and good deed as an outward behavior are complementary.
If faith is established in one’s heart, its effects are manifested in his actions so that what he does becomes pure and righteous. Faith in humans is like a bright light that lightens its surroundings. The effects and reflections of faith can be seen in one’s eyes, ears, tongue, hands, feet and thoughts. Hence, a faithful man or woman does not do anything unless it is in accordance with their faith and beliefs.
Faith is like a root and good deeds are its fruits. When the fruits are juicy and sweet, it means the root is healthy and well.
God likes such people who are pure both in the inside and outside. God has promised them to be successors of Him on earth: “Allah has promised to those of you who believe and do good that He will most certainly make them rulers in the earth as He made rulers those before them,…” (Surah An-Nur, verse 55)
Of course divine promises for such people are not limited to this world as God will also grant them a good place in the Hereafter: “A Messenger who recites to you the clear communications of Allah so that he may bring forth those who believe and do good deeds from darkness into light; and whoever believes in Allah and does good deeds, He will cause him to enter gardens beneath which rivers now, to abide therein forever, Allah has indeed given him a goodly sustenance.” (Surah At-Talaq, verse 11)
Those who have no faith may sometimes do good things but it is temporary. What guarantees good deeds is a faith that has roots in the depth of one’s heart.
source:iqna