The Messenger of Allah (saws) said , "He who thanks Allah after eating earns the same reward as one who fasts and desists from eating".
[Bukhari and Tirmidhi]
Explanation : Thankfulness to Allah is a supreme act of worship which requires only a few moments . One must thank Allah for all his boons and mercies, whether big or small. One should thank Allah when on returning home, he finds his family safe and well, when he eats food when his hot brow is fanned by cool breeze, when he sees his child happily at play; in other words everything which pleases and comforts should be acknowledged with thanks to the One Allah who is the Real and the Ultimate Source and intone his thanks, he should do it in his heart.
Our learned elders have instructed that upon going to bed and before falling asleep, one should think of Allah's gifts and boons and thank Him for everyone of them. For instance, one should think of the good health of his family and himself; of the house which he lives in, of the comfortable bed lie sleeps in, of his own safety and that of his family and thank Allah for these Divine mercies before closing his eyes in sleep.
Real and true thankfulness to Allah implies changing ones ways to into those that please the Almighty, but if one merely expresses his thankfulness in his heart or by mouth, it too is an act of great worship. This can lead to a change for the better in other deeds.
Shaikh Sa'di has said that if one ignores other boons and mercies, life itself is a boon of highest order, in so fir as the act of breathing itself has two boons of inhalation and exhalation; if breath, goes in and does not came out it is death and if breath goes out and does not cone in it is again death. Hence every breath has two boons for which Allah must be thanked. However even if one thanks Allah once with every breath, it is still insufficient; so how can one adequately thank Allah for other boons and mercies?
Though it is impossible to thank Allah adequately. but thanking Him to the best of ones ability is a pleasing to Allah and earns countless merits, and also leads to the grant of further boons and mercies, one also get closer to Allah.