John Gill Commentary John 1:43

"On the morrow he was minded to go forth into Galilee, and he findeth Philip: and Jesus saith unto him, Follow me." — John 1:43 (ASV)

The day following
Not the day after John had pointed out Christ, as the Lamb of God, to two of his disciples; but the day after Simon had been with him, being brought by Andrew:

Jesus would go forth into Galilee ;
from where he came to Jordan, to John, to be baptized by him; and which being done, and his temptations in the wilderness over, it was his will, resolution, and determination, to return to Galilee, the place of his education and conversation, till this time. Therefore he chose to begin his ministry, and miracles, there, both to give honour to it, and to fulfil a prophecy in (Isaiah 9:1Isaiah 9:2); and besides this, he had doubtless another end in going thither: which was to call some other disciples that dwelt there:

and finds Philip ;
as he was going to Galilee, or rather when in it; not by hap or chance; but knowing where he was, as the shepherd and bishop of souls, looked him up and found him out, and called him by his grace, and to be a disciple of his; (See Gill on Matthew 10:3);

and says unto him, follow me ;
leave your friends, your calling, and business, and become a disciple of mine: and such power went along with these words, that he at once left all, and followed Christ; as the other disciples, Peter, and Andrew, James, and John, and Matthew did, as is recorded of them, though not of this; but the following history makes it appear he did.