Eikev

The חפץ חיים brings our attention to three pesukim in this parsha, each with a similar theme, each worded differently. The first one states, ושמרת את מצות ה' אלקיך ללכת בדרכיו וליראה אתו to keep the mitzvos of 'ה, to go in his ways & to fear Him. Note that it says first go in 'ה's ways, then fear him.

A little later, the parsha says כי אם ליראה את ה' אלקיך ללכת בכל דרכיו ולאהבה אותו only to fear 'ה, go in his ways & to love him. Note that here it says to fear Him before it says to go in His ways.

Then, toward the end of the parsha, it says: כי אם שמר תשמרון וגו' לאהבה את ה' אלקיכם ללכת בכל דרכיו ולדבקה בו to keep the mitzvos, to love 'ה, to go in His ways & to cling to Him. Here it puts going in His ways after love of 'ה but before clinging to Him.
Why the change?

The חפץ חיים explains that there are three levels in the service of 'ה; one is fear. We know that we have to fear 'ה.
The second level is love, to serve 'ה not out of fear of punishment, but rather out of love.

The third level is דבקות, clinging. The רמב"ן explains that the difference between love & clinging is that love is something that could be periodical. Sometimes one has intense love & sometimes the feeling isn't that strong. On the other hand, דבקות is an intense love that is in one's heart continuously and allows one's soul connect to 'ה.

The חפץ חיים continues that the Torah is teaching us that one cannot attain  any level unless one accustoms oneself to go in the ways of 'ה. This includes being merciful, compassionate, & kind. That's why the first posuk says, first go in His ways & then fear Him, for to even attain the simplest level of fear one must go in 'ה's ways and perpetuate kindness.

Then, the next posuk teaches us that even after you attain the level of fear, don't think that you can just sit all day & learn or delve into holy thoughts. Rather the posuk says, first fear me then go in my ways & then love me. It's teaching us the process to get to the next level. Once you attain the level of fear, reaching the level of love is only through going in His ways & doing kindness.

The last posuk refers to one who has attained this level of love for 'ה . This person, in all likelihood, removes himself from the pleasures of this world & might feel that he now has the right to immerse himself only in spiritual pursuits in order to attain the third level of clinging to 'ה. He might think that he doesn't have to associate with other people or waste time helping others. For him the posuk says, even after one reaches the level of לאהבה את ה' אלקיכם, one must continue   ללכת בכל דרכיו , going in His ways of doing kindness for people. Only then the posuk concludes  ולדבקה בו you will cling to Him. Only by emulating 'ה's ways of kindness & mercy can one achieve the ultimate closeness to 'ה.

There's a story told about the Steipler that exemplifies this point. Once, a young kollel man went into him to ask how he should structure his day: what he should learn in the morning, night, afternoon etc. After the Steipler finished directing him in what manner to spend his day, the young man got up to leave. The Steipler called him back & asked him to sit down & told him, "You know that you have to help out around the house too". The man was flabbergasted. He thought the Steipler was calling him back to tell him to learn kabbala  or something of that nature but to help around the house? The Steipler repeated, “I see that you are a big masmid, but you must also know that you also have to help around the house. The man said, “my wife is a big tzadekes & she wants me to only learn & do nothing else.” The Steipler answered, “that's her mitzva, but your mitzva is to help her. Every day when you come home, remember to ask her how you can help.”

This demonstrates how important it is to help other people & not feel that there are more important things to do. Rather, we have to follow 'ה's lead & be merciful, compassionate & kind, enabling us to get as close as we can to the level of דבקות to 'ה!