I am the last of the three

With hopeful eyes, you gaze at me

Hoping to catch up

Never do you really see

The drink that's in your cup

You think that I've got all the answers

And for all I know, I might

I might have the cures for colds and cancers

But you have to give me the might

You never know what secrets I hold

The gifts and curses I bear

Wait long enough, and you'll have been told

The knowledge I can share

What am I?

Are you

The future?

Title: I am the last of the three

Past, present, and the future

With hopeful eyes, you gaze at me
Hoping to catch up
Never do you really see
The drink that's in your cup

Kids can't wait to grow up, and in many western cultures it's common to expect that the future brings better things, even though we would probably be better off concentrating on what we already have ("the drink that's already in our cup"), trying to find happiness there.

You think that I've got all the answers
And for all I know, I might
I might have the cures for colds and cancers
But you have to give me the might

Maybe things actually will get better, but not without us, in the present, putting in the effort.

You never know what secrets I hold
The gifts and curses I bear

The future moves ahead just as quickly as the present, so we can never know the future.

Wait long enough, and you'll have been told
The knowledge I can share

As you grow older, you learn things that were, from your earlier point of view, in the future, so you get to know your portion of that future. And then the future cannot tell you any more knowledge, because you'll die. Possibly in a freaky atomic bear-shark-hybrid related incident. You don't know that you won't!

• Nicely done! I was thinking more of "Tomorrow", but you got the idea! – Cubemaster Jan 31 '19 at 14:09

Are you

Technology

With hopeful eyes, you gaze at me

I am looking at me computer.

Hoping to catch up

Keep up with the latest technological advances.

Never do you really see

There is always new technology you do not heart about until 3 years.

The drink that's in your cup

T for technology

You think that I've got all the answers And for all I know, I might

I might have the cures for colds and cancers

Hospitals are using more and more technology.

But you have to give me the might You never know what secrets I hold

You have to use technology to make it.

The gifts and curses I bear

Well, technology may spy on you.

Wait long enough, and you'll have been told The knowledge I can share

You can learn a lot form technology.

Title

On wikipedia it put technology in the category of the Modern era with follows the Paleolithic and Neolithic era. Therefore the last of three.

• Hello old friend! A valiant attempt, but not quite. I do like this answer though – Cubemaster Jan 30 '19 at 19:20

My guess:

A parent

With hopeful eyes, you gaze at me

From the child's perspective

Hoping to catch up

As a child, always wanting to be older

Never do you really see The drink that's in your cup

As a child you don't really appreciate how well things are. You always keep looking ahead rather than enjoying the present

You think that I've got all the answers

As kid's often do, always believing in their parents

And for all I know, I might

As a parent you never know what you might achieve in the future

I might have the cures for colds and cancers

Depending on your area of expertise, anyone could really have this knowledge

But you have to give me the might

Children encourage parents and provide an additional meaning to life

You never know what secrets I hold

As a child, parents don't often reveal their secrets to you

The gifts and curses I bear

Life is often mixed and most parents choose to protect their children from the worst of life

Wait long enough, and you'll have been told

The knowledge I can share

Parents have the most to share to their children

From a particular perspective, the answer can be:

The Holy Spirit
Out of God, Jesus, and the Holy Spirit, the Holy Spirit, while not necessarily third in power, is usually listed third in the list when being spoken of, the last of three.

While this is not meant to be a theological post, I will leave out the references, only validating claims.

With hopeful eyes, you gaze at me
Hoping to catch up

A Christian awaits the power of the Holy Spirit

Never do you really see
The drink that's in your cup

Often, a person neglects to take advantage of the present moment, a failure of character, as well as a lack of faith [in the power of God hence Holy Spirit].

You think that I've got all the answers
And for all I know, I might

The Holy Spirit does have all the answers, think about this not from the Holy Spirit speaking, but rather the perception of the Holy Spirit by a believer who lacks sufficient faith to grasp the omniscience of God. They "think" the Holy Spirit has all the answers, but can't fully grasp it yet.

I might have the cures for colds and cancers
But you have to give me the might

The Holy Spirit has the power of healing of all sorts. "Might" instead of certainty, because "you have to give me the might", which is due to the fact that the power of the Holy Spirit on Earth is limited by the receiver's faith to receive that healing, among other factors.

You never know what secrets I hold
The gifts and curses I bear

Since the power of God is infinite, a person can never know all the secrets held; there are gifts to the friends of God, as well as curses to the enemies of God.

Wait long enough, and you'll have been told
The knowledge I can share

With patience and perseverance, the Holy Spirit will impart wisdom and knowledge, although it may take some time for the person's faith to grow great enough to receive this wisdom.

It is

TIME

With hopeful eyes, you gaze at me

Hoping to catch up


with the clock

Never do you really see


can't see time

The drink that's in your cup


letter T (tea)

You think that I've got all the answers


time will tell

And for all I know, I might


letter I (I might)

I might have the cures for colds and cancers


time cures diseases

But you have to give me the might


letter M (from might)

You never know what secrets I hold


secrets held in time

The gifts and curses I bear
Wait long enough, and you'll have been told
The knowledge I can share


from the heading (last of the thre'e')

the lettter E