On this Lord told him to offer Him some water only. Somehow there was no water also available with Him at that time so he showed his inability to serve water also to the Lord. On this, Lord asked him to serve Him with simple leaves of a tree but he could not even bring the leaves to the Lord as had got hurt in his leg & could not walk. On this, Lord told him to “Serve Him in his mind only by thinking & loving the Lord in his mind”. So the devotee thought of Lord & prayed Him in his mind with great Love & Lord became very happy with him.”
In Bhagwat Gita also Lord says that:
"patram puspam phalam toyam
yo me bhaktya prayacchati
tad aham bhakty-upahrtam
asnami prayatatmanah" (Bhagwat Gita: Chapter Nine verse 26)
"Sri Krishna said: If one offers Me with love and devotion a leaf, a flower, fruit or even water, I will accept it."
"yat karosi yad asnasi
yaj juhosi dadasi yat
yat tapasyasi kaunteya
tat kurusva mad-arpanam" (Bhagwat Gita: Chapter Nine verse 27)
"Sri Krishna said: Whatever you do, whatever you eat, whatever you offer or give away, and whatever austerities you perform—do that, O Arjuna, as an offering to Me."
In Bhagwat Gita also Lord say that:
"tasmat sarveshu kaleshu
mam anusmara yudhya ca
mam evaishyasy asamsayah" (Bhagwat Gita: Chapter Eight verse 7)
"Sri Krishna said: Therefore, Arjuna, you should always think of Me in the form of Krishna and at the same time carry out your prescribed duty of fighting. With your activities dedicated to Me and your mind and intelligence fixed on Me, you will attain Me without doubt."
So lets always think of Lord Krishna and do our prescribed duty. By doing so we shall always dwell our mind in the God. Living in this way we shall always be happy & in the end go to the Lord’s place where we shall get a blissful life forever.
Jai Sri Krishna